Hi All,
I put my 1973 Hare Scrambler together but just can't get it started.
1) The Motoplat ignition has been load tested, the magnet re-magnetized. There is spark when watching the removed spark plug.
2) I am using a Champion L78C spark plug which should be the equivalent of the NGK B8SV. I couldn't find the NGK.
3) I re-checked the ignition timing, it is set at 2.55 mm BTDC (I rotate the rear wheel back after reaching TDC and measured with a dial indicator).
4) I tested the engine's (freshly rebuilt) compression and measure 165 psi. I think this should be sufficient, I didn't mess up when setting the deck height I conclude.
5) There is gas in the engine. After kicking the engine over a number of times (>30) the spark plug is wet. I cleaned it a number of times in the process. I use 98 octane ethanol-free leaded gasoline (mixed from 112 octane race gas and ethanol-free 90 octane pump gas). I am using a 1:32 pre-mix ratio (Maxima Super M synthetic race 2-stroke oil).
6) I installed all new jets in the Bing 54 carburetor: new float needle and seat (I measured the fuel volume to be about 40 ml when the float valve is blocking, the floats are adjusted parallel as described in the instructions), a 46-281-01 jet needle (set to second notch from top), a 290 needle jet, a 165 main jet, and a size 40 pilot jet. This is as close to the manual as I could get.
7) I am using a foam air filter.
8) I have checked all air ways (inlet and outlet) and found no obstructions in there (rags or debris).
There is spark, gas, and compression! I also tried push starting but that doesn't work either, the engine has good compression and the rear wheel blocks at the kind of hill we have here. I am kind of at my wit's end at this point. Any ideas what else I could try?
Cheers
Andreas
Have you changed plugs trying another, possibly one from a running motorcycle that is for sure not fouled, or another brand new one?
Good luck...
Paul
Hi Paul, I am using a brand new spark plug. The only thing I could think of plug wise is to get an NGK, but I can't find one here.
Thanks for your input!
Andreas
Have you changed the plug cap? As I recently discovered, Motoplat ignitions will only work with a non-resistor type plug cap.
A new plug does not guarantee good. Change plugs & squirt some gas/oil into plug hole & try it. It takes a great deal of gas to fire a dead cold KTM engine. Try to find a NGK B8HS plug. Mike
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R
Thanks for the ideas! Actually I do use a new, non-resistor cap. I think I'll try Michael's suggestions, both of them!
Cheers
Andreas
Make sure that the air filter is not over oiled. Try starting with no filter.
Is the jet needle seat facing the correct direction?
_____________________________________________________________________________________
"We the willing, led by the unknowing, are doing the impossible, for the ungrateful. We have done so much, for so long, with so little, that we are now qualified to do almost anything, with nothing."
1972 Penton Berkshire 100
1983 Husqvarna 250 XC
2011 Jayco 31.5 RLDS
2009 Chevy 2500 HD Duramax
I haven't oiled the air filter yet, so this ain't it either. Which part is the jet needle seat?
Thanks!
Andreas
sounds silly but check the pipe.i have seen plugged pipes before
dennis l.brown
Actually a clogged connection sounds quite plausible. No gas flow=stalled engine. I've checked some time back:
(http://i1341.photobucket.com/albums/o746/andreas_g_piepke/Penton/100_4120_zps3ffee414.jpg)
I can put the plumbing implement seen in the picture above through the pipe until it reaches the spark arrestor. I was worried to find some residue from "biological activity" in there. However, nothing was found. I even fashioned a little mouth piece and verified that I can blow air through the pipe.
Cheers
Andreas
After looking at the picture of your bike it appears to have a freshly painted frame. Did you remove the paint on the engine to frame contact points and apply dielectric grease to ensure a good ground path ?? The motoplat ignition must have a very good ground path to work correctly. Let us know what you find.
Dave McCullough
If you cant get it running, I'll have it! [:p][:p][:p]
Andreas wrote -> 3) I re-checked the ignition timing, it is set at 2.55 mm BTDC (I rotate the rear wheel back after reaching TDC and measured with a dial indicator).
Andreas, When timing, it's easier just removing the right hand side cover, and turning the flywheel with your hand. I would think more accurate also.
Bob
On all my Motoplat ignition bikes, I run a separate ground wire from the coil mount to the engine or stator mount plate to insure a good ground, so I don't need to remove paint from the frame or worry about loosing ground due to corrosion or bolts loosening from vibration. Mike
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R
What I called the "seat" is actually the atomizer or vaporizer.
It has a half moon cutout on the top where the needle "seats" into it.
The open side should face the engine so that as the needle is raised by the slide that fuel can be drawn from the float bowl.
If inserted the wrong way the incoming air flow would not allow fuel to into the engine.
_____________________________________________________________________________________
"We the willing, led by the unknowing, are doing the impossible, for the ungrateful. We have done so much, for so long, with so little, that we are now qualified to do almost anything, with nothing."
1972 Penton Berkshire 100
1983 Husqvarna 250 XC
2011 Jayco 31.5 RLDS
2009 Chevy 2500 HD Duramax
I have seen the Motoplat connectors go bad with corrosion where the wires are crimped on, happened after to years of use back in the '70s!
The ground wire is another good idea. I'll put one in once I have the new NGK B8HV spark plugs I ordered on Ebay.
I have the needle seat installed so the open end faces the cylinder. Initially I had this the other way around. Upon closer inspection with a magnifying glass it turns out that it has a tiny little hole drilled in its side. This hole aligns with the little air channel in the carburetor. I think this important for starting and idling. I actually made sure, with a tiny wire, the these two holes align with each other when I re-assebled the carb.
Cheers
Andreas
Sounds like you have checked everything, and in quite a workmanlike manner.
The only thing that sounds strange seems to be your manner of timing the ignition. Do you have a motoplat timing pin?
It is a thin piece of hard wire that fits in the small hole in the circumference of the flywheel and locks into a matching hole in the stator. If you don't have one a very small punch will work.
Leave the stator screws somewhat loose, lock the pin into both the flywheel and stator, find TDC by slowly spinning the flywheel, then gently roll counterclockwise until you reach the setting. Remove the pin and flywheel, tighten stator screws.
Recheck the timing by slowly rotating and catching the pin in the locked stator, torque the flywheel and ready to go.
I've never heard of the wrong brand of plug being a reason for not starting. Performance maybe, but not starting...
_____________________________________________________________________________________
"We the willing, led by the unknowing, are doing the impossible, for the ungrateful. We have done so much, for so long, with so little, that we are now qualified to do almost anything, with nothing."
1972 Penton Berkshire 100
1983 Husqvarna 250 XC
2011 Jayco 31.5 RLDS
2009 Chevy 2500 HD Duramax
Hi Clark,
I just want to make sure I did this right. Below please see a picture of the vaporizer and the little hole in its side:
(http://i1341.photobucket.com/albums/o746/andreas_g_piepke/jets_details_zps9edc810d.jpg)
I installed it such that it aligns with the air channel shown in the picture below:
(http://i1341.photobucket.com/albums/o746/andreas_g_piepke/carb_back_zps296245f1.jpg)
This required some back and forth as there is no feature guiding or locking the vaporizer into the right position. I used a very fine wire after installation to assure that there is a way for the air to go through.
Is this the way the jets should be put together or the wrong way around? I better get this right!
Thanks for brainstorming this with me!
Andreas
Andreas,
I've never been instructed about aligning the holes in the side, but I am sure that they are part of the process. On the top of the atomizer it is a semi-circular opening. The shielded part should face the air box, the open part should face the cylinder.
We always inserted it in the correct direction with the carb upside down, and screwed in the jet holder while the carb was still upside down.
Have you had a chance to check the timing?
_____________________________________________________________________________________
"We the willing, led by the unknowing, are doing the impossible, for the ungrateful. We have done so much, for so long, with so little, that we are now qualified to do almost anything, with nothing."
1972 Penton Berkshire 100
1983 Husqvarna 250 XC
2011 Jayco 31.5 RLDS
2009 Chevy 2500 HD Duramax
Clark,
Is the vaporizer a monolithic part or can the top section with the shroud be rotated relative to the lower part with the hole? I would hate to try and damage the part in the process.
Thanks for your input!
Andreas
In the last photo of the vaporizer the small hole side should face the cylinder. The shield or taller portion should face the air box side. Unscrew the needle/main jet assembly and give it a light tap from above with a punch or dowel in the center hole to knock it out and reposition if necessary.
Dale Fisher
Penton Owners Group - President/Memberships
Mudlark Registry
Facebook - Cheney Twinshock Racing Group - Administrator
'70 Six-Day 125 - V2017
'71 Six-Day 125 (Dave Fisher's) - V5553
'72 Mudlark - W257
'73 Jackpiner - 175 21159727
'74 Berkshire 100 - 40171056
'98 HP-14 Hi-Point
And some silly other bikes...
It's a one piece part. Lightly tap it out with a small block of wood and re-insert it with the shield facing the airbox. The holes will take care of themselves.
I never use wire or metal on delicate brass parts - but I'm paranoid.... and clumsy...
_____________________________________________________________________________________
"We the willing, led by the unknowing, are doing the impossible, for the ungrateful. We have done so much, for so long, with so little, that we are now qualified to do almost anything, with nothing."
1972 Penton Berkshire 100
1983 Husqvarna 250 XC
2011 Jayco 31.5 RLDS
2009 Chevy 2500 HD Duramax
OK so I may have the vaporizer in there the wrong way around! I'll check this weekend and turn it around if needed. I'll keep you posted.
Cheers
Andreas
P.S.: Clark, I also ride a 1973 Norton Commando. Last year it wouldn't start any more. After carefully cleaning the pilot air lines in the Amals it now starts reliably again. A thin wire, used carefully, can sometimes do wonders.
Hi All,
2/28/2015
I installed a new NGK B8HV spark plug. I had a look into the carburetor too. The vaporizer is actually installed in the correct orientation with the shroud oriented toward the air box.
(http://i1341.photobucket.com/albums/o746/andreas_g_piepke/100_4188_zpsjoez4apz.jpg)
After some more trying I finally managed to start the engine:
https://www.youtube.com/watch?v=n_c3xY6JiLk
It still doesn't run right though. At full throttle the engine doesn't rev higher than what you can see in the video. Anything less than full throttle and the engine dies. It also smokes a lot. Any thoughts about what the problem could be? I listed all basic settings earlier in this post.
Thanks
Andreas
When setting the timing, I always just rotate the flywheel by hand to get the proper setting, never tried rotating the wheel, are you sticking the pin through the hole in the flywheel into the stator? My thoughts are faulty motoplat, I had one where the engine would run but would not rev and my other thought is, is the piston in correctly, arrow towards the exhaust? The slide in the carb, does it have the slot for the manual choke slide or is it a solid slide?
The piston is installed the in the right orientation with the window toward the inlet, have a look:
(http://i1341.photobucket.com/albums/o746/andreas_g_piepke/100_3930_zpsxad51hnw.jpg)
If you put the engine into turning the rear wheel gives good leverage and in turn allows to position the piston accurately. I've measured this to 0.01 mm and don't believe that some small inaccuracy can have such a big effect. Yes I am using a self fashioned locator pin cut from a cloth hanger). The Motopalt and coil have been tested at Penton Racing Products before installation. I think these components are good, there is spark when I take the plug out. I don't think this is it.
Cheers
Andreas
I can think of a couple things. Sometimes when you re-assemble the carb, you can get the needle assembled to the slide correctly. You have been really busting your butt on this bike and sometimes frustration makes you make a simple mistake. Make sure you have the clip where you want it, and the slide assembly is put together correctly.Make sure the jetting is what you want and need.
Also make sure the choke is working correctly. I have seen guys get confused on which way to push the lever to put the choke on and take it off. Done that myself a lot. If it's not coming all the way off, it will make the bike run super rich. Kind of what it sounds like in the video, and can explain the smoke.
Your pipe has a SuperTrapp style silencer. Maybe something in the discs isn't right and restricting the exhaust. Kind of sounds like that also in the video. If it starts and runs at all,you are in the ball park. Just a few small details to work out yet.
I am really admiring the job you have done with the bike, and the photos you have posted have been most excellent. Almost like being there! Good luck with it and keep plugging away.
Type at you later,
Dan McEntee
Once while putting my GS 400 Bing carb back together I mistakenly installed the needle and clip assembly inside the plastic cup rather than under the plastic cup. The bike ran, but terribly. Took forever to figure it out......My point is sometimes something very simple can make you scratch your head.
Just a thought. Maybe bottom end is full of gas, Try starting bike, holding throttle wide open and shut off both fuel valves. May take a minute or even 2 to use up fuel in bottom end. If it is full it will suddenly "clean out" and run fine. Then turn petcocks back on and enjoy!
Ted
There is a crankshaft case drain Allen screw directly under the centerline of the crank to allow draining any pooled fuel. Mike
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R
Anybody got 2c I can borrow?
My favorite bog problem mistake was the little dust wipers left in the intake and exhaust ports. [:I]
How's your base compression anyway? Near impossible to check that one I know...
Got a big hill to push it down? If the crank seals are suspect, it might start with the piston speed way up there...
Raymond
Down East Pentons
Hi All,
BINGo! Steve had the right idea. Indeed, I had the needle and its clip installed above the plastic holder instead of under. Looking at the parts list this is obvious after Steve pointed it out. I fixed this issue and the bike starts much easier and revs up when in neutral. Have a look at the little video I've posted:
http://youtu.be/pmjiYrEN3pA
Now with this problem fixed the job still isn't done. The bike doesn't rev up when put into gear. What you can see in the video is about the top speed I can achieve. So something still isn't right. The bike should be a little more lively than a moped, I guess.
Keep on analyzing, this gets me on the right track. Thanks again!
Andreas
It sounds loaded up, and it seems like a lot of smoke from the exhaust. Too much fuel/oil or not enough air....
Couple more shots in the dark:
Any chance the clutch side crank seal was nicked when installing the crankshaft? Is there oil around the exhaust port or dribbling from the supertrapp? If yes - pull the clutch cover & see if you smell gas in the crankcase oil.
Do you have the supertrapp nuts too tight? The discs should slightly rattle when tightened correctly. There should be no other spark arrestor in the system when using a supertrapp. You can also try running without the discs & end cap. With the discs removed try blowing air through the exhaust & check the output.
Are you sure the carb floats are working correctly? Metal or viton tipped float needle? If metal - reseat it by gently tapping it into the seat with the eraser end of a pencil. Before the viton ones came out we had to do this trick regularly to create a new lower seat. Check the float level again by removing the bowl while the carb is still mounted & turning the petcocks on.
Any chance you mis measured the fuel/oil in your pre-mix?
_____________________________________________________________________________________
"We the willing, led by the unknowing, are doing the impossible, for the ungrateful. We have done so much, for so long, with so little, that we are now qualified to do almost anything, with nothing."
1972 Penton Berkshire 100
1983 Husqvarna 250 XC
2011 Jayco 31.5 RLDS
2009 Chevy 2500 HD Duramax
Hi Clark,
Thanks for sharing your ideas with me. I am responding below.
Cheers
Andreas
Quotequote:Originally posted by SouthRider
It sounds loaded up, and it seems like a lot of smoke from the exhaust. Too much fuel/oil or not enough air....
>>I will definitely try this out.
Couple more shots in the dark:
Any chance the clutch side crank seal was nicked when installing the crankshaft? Is there oil around the exhaust port or dribbling from the supertrapp? If yes - pull the clutch cover & see if you smell gas in the crankcase oil.
>>I think the chances for this are minimal. I put a new seal in. On the left side you just put the crank shaft through and that's it. No alignment issues or pressing needed or anything like this.
Do you have the supertrapp nuts too tight? The discs should slightly rattle when tightened correctly. There should be no other spark arrestor in the system when using a supertrapp. You can also try running without the discs & end cap. With the discs removed try blowing air through the exhaust & check the output.
>>This is a good idea! I'll try this out next weekend. In addition I'll remove the air filter to further improve gas flow. Maybe that'll identify the issue.
Are you sure the carb floats are working correctly? Metal or viton tipped float needle? If metal - reseat it by gently tapping it into the seat with the eraser end of a pencil. Before the viton ones came out we had to do this trick regularly to create a new lower seat. Check the float level again by removing the bowl while the carb is still mounted & turning the petcocks on.
>>I had the Bing people install a new, Viton tipped, float needle. However, I did have to adjust the float level. I measured the float needle tightness and amount of fuel in the bowl by means of filling the carb with a syringe. I can put 40 ccm in there before the float needle blocks the flow. Is this too much? How much fuel needs to be in there for proper operation? I had measured this volume before changing the needle and found about 40 ccm too. But who knows whether this was correct. I find the guidance of the manual, basically eyeballing the float location, quite inaccurate, thus, the measurement of the gasoline volume (gasoline volume in there is the primary quantity of interest).
Any chance you mis measured the fuel/oil in your pre-mix?
>>No I don't think so. I was quite careful there.
_____________________________________________________________________________________
"We the willing, led by the unknowing, are doing the impossible, for the ungrateful. We have done so much, for so long, with so little, that we are now qualified to do almost anything, with nothing."
1972 Penton Berkshire 100
1983 Husqvarna 250 XC
2011 Jayco 31.5 RLDS
2009 Chevy 2500 HD Duramax
We never measured the fuel in the bowl, and I don't know if that spec exists.
Rotate the carb to the side & remove the bowl - rotate it back to normal position. Turn on the petcock while holding the float up & eyeball the point at which the fuel flow stops. As described in the manual it should shut off when the floats are parallel to the carb body.
It's also possible that the engine is just loaded up with accumulated fuel from trying to get started the first time, or that too much assembly oil was used in the top end.
Get it running and keep it running till the engine gets warm. Sometimes they just need a few minutes to clean out.
I know you put new jets in the carb, but there could be trash in them from the fuel tank. If nothing else works take the carb apart again & look through all the jets to see if they are still clean (not likely as the bike does sound loaded up).
_____________________________________________________________________________________
"We the willing, led by the unknowing, are doing the impossible, for the ungrateful. We have done so much, for so long, with so little, that we are now qualified to do almost anything, with nothing."
1972 Penton Berkshire 100
1983 Husqvarna 250 XC
2011 Jayco 31.5 RLDS
2009 Chevy 2500 HD Duramax
When there is excessive fuel in the crank case, there is a drain screw below for that reason.
Posted - 03/01/2015 : 07:59:06 AM
Just a thought. Maybe bottom end is full of gas, Try starting bike, holding throttle wide open and shut off both fuel valves. May take a minute or even 2 to use up fuel in bottom end. If it is full it will suddenly "clean out" and run fine. Then turn petcocks back on and enjoy!
Ted
Did you never try this? I know you had needle too high but give this a try.
Someone also mentioned draining the crank to accomplish same thing.
Hi All,
So I did some work on the bike this weekend.
1) I ran the float bowl empty three times to clear out any excess gas in the crank case.
2) I slightly loosened up the super trap disks.
3) I cleaned out the air box and found gasoline in there.
I ran the bike without air filter for a little and noted that it ran better.
4) I removed the carb to adjust the fuel level in the float bowl. As the float needle seat is a (Bing) custom part I was not sure that "float parallel" still results in the correct amount of fuel in the bowl. So I measured (on the bench) the gasoline volume that fits into the bowl until the float needle blocks. I found 50 ml and concluded this is too much. Before sending the carb for rebuild I measured 40 ml. So I adjusted the tab on the floats until the needle would block with 40 ml of gasoline in there. This now requires the floats to be a slight upward angle when the carb sits on its head on the bench.
5) I moved the jet needle from the second to the top notch. To make it run leaner.
After that the bike ran yet better but wouldn't want to take gas when transitioning from low to intermediate revs.
6) I changed the needle jet from 2.90 to 2.74 and put the needle again into the second notch.
The bike yet runs a little better. Have a look at the little video I posted:
https://www.youtube.com/watch?v=9LGQZ_XJwUI
I am still not happy as the engine now takes gas unwillingly at low revs, the transition to mid revs is rough and kind of sudden. Currently I have a type "0" slide installed. I'll try a type "2".
Thanks for all your tips. Keep on sending your observations, I want to get this run well!
Cheers
Andreas
2.74 is too lean in my opinion, especially for this time of year. Stock is 2.83, try one of those now that you think you might have the float level close. I still think most of your problems are stemming from that modified float needle/seat.
Brian
Hi Brian,
I can try this. One problem: Al Buehner doesn't carry this size needle jet for a 36 mm Bing 54, according to his web page. I'll need to get this jet perhaps from Bing. Once I place an order with them I might as well get an assortment of jets. Could you advise which sizes of needle jet and main jet the prudent rider has in stock? This way I could order a bunch at once. Making these adjustments certainly improved things, I am just not there yet.
Thanks for your input!
Andreas
I have a 2.83 in my 250 and I have never had to change that for weather or altitude, I do have to move the clip position but not the needle jet itself. If you order from Bing I would get a 2.83 and the next ones up and down, which I think are 2.80 and 2.86.
Brian
Thanks for the guidance Brian. I'll contact the Bing Agency people to see what they have. Another thing: I have three main jets: 155, 165, and 170. Would you recommend any other sizes?
Cheers
Andreas
What size pilot jet are you running? The pilot jet combined with other jetting factors control the off idle response and I couldn't find a reference on what size the pilot jet is in your carb. Stock for the 73 250HS is a 40 pilot jet with a 165 main jet and 283 needle jet and the jet needle clip in the 2nd position according to the instruction book. Mike
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R
Michael, I am currently running a size 40 pilot jet. I do have a used size 50 pilot jet at hand. I have a 165 main jet installed. The needle is in the second position, however, with a 274 needle jet. I have already sent an email to Bing Agency to see whether they have other needle jets in stock. One more thing: my slide has a "0" stamped into its bottom. Al Buehner's web page lists type 2 slides for this model. Would you know whether or not I have the right slide?
I agree that my 274 needle jet may be a bit too small. After all the adjustments I did this weekend the spark plug is no longer wet but light brown, indicating that the mix might be a bit too lean.
The number of possible combinations of all these components is VERY large. Input from this group regarding what works is therefore a great help. Thanks for your input!
Cheers
Andreas
Quotequote:Originally posted by 454MRW
What size pilot jet are you running? The pilot jet combined with other jetting factors control the off idle response and I couldn't find a reference on what size the pilot jet is in your carb. Stock for the 73 250HS is a 40 pilot jet with a 165 main jet and 283 needle jet and the jet needle clip in the 2nd position according to the instruction book. Mike
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R
Sorry, but the manual does not list the slide information other than part # 22-746/1. is the o-ring at the top of the carb that seals the lid in good shape? Bing has them. Mike
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R
Im running
165 main
283 needle jet
45 pilot
Brian
OK so the 283 needle jet seems to be what people are using. I already sent an email to Bing Agency to inquire about availability. My main jet seems right. The number 40 pilot jet is probably close enough. I might get a number 45 too, as used by Brian, once I order from Bing.
Thanks for your input!
Andreas
Since you have gone this far with the carburetor, I would replace the brass float bowl seat, float needle, float itself, clip and pin as well. I have done this on my Penton, 73 Husky and 74 Can Am Bing carburetors, and it made a big difference. The float that was in the Can Am was old and heavy. It actually sank when I put it in a separate larger bowl of gas. Try to find a new black one. Bing doesn't have them, but they work the best. But the white ones will work.
If all the carburetor re-building doesn't work, I would remove that silencer, just to see if it makes a difference.
Actually, I would have done that first.
1990 KTM 125 - Del Orto Carb
Cannot get it to run start and need help. Any ideas ?
Thanks, Victor
Or an offer ?
Hi Victor,
Any luck yet with your bike? Does it have spark? Is there gas in the bowl? Is the spark plug dry? Did you try a new spark plug? Sometimes starting issues can be caused by plugged air channels in the carb connecting to the pilot jet. Obviously I have no way to diagnose your problems just a few shots in the dark.
Good luck
Andreas
GB was correct in suspecting the float. The foam (white) float get heavier with age. they can be checked with a gram scale , I am out of town at present and can't recall correct weight. Bing no longer imports the Black 310 floats. I don't know if they are no longer made or that this completely cures the white float problem and you wont be buying replacement foam ones. I ran 310 floats on all my Pentons 125/250 and they ran great. Talk to anyone riding an Airhead BMW and they will all tell you that the white floats are a common issue. DON"T TRUST OLD FOAM FLOATS PERIOD!
Lot of Penton parts for sale. Inquire via email.
Hi All,
Here a picture of my assortment of carb components:
(http://i1341.photobucket.com/albums/o746/andreas_g_piepke/Penton/100_4204_zpsgz6byf7l.jpg)
I also tried a size 2 slide (left), a size 0 slide (right) was installed in the carb:
(http://i1341.photobucket.com/albums/o746/andreas_g_piepke/Penton/100_4208_zpsxhvp5ebt.jpg)
I tried some 12 different combinations of components and settings. The size 2 slide didn't work at all, the bike ran way to rich. After my experimentation I found a combination that works much better than what I had initially:
40 pilot jet
170 main jet
2.80 needle jet
46-281-01 jet needle
size 0 slide
I further moved the ignition "time" from 2.55 mm BTDC to 2.25 mm BTDC.
I'll post a video of a test run for you to critique once it stops raining here. It seems I am making some progress!
Cheers
Andreas
P.S.: Yes I did install a new rubber ring on top of the carb. I don't know what to say about the float issue. The job of the floats is to maintain a consistent amount of fuel in the bowl. I took the bowl off multiple times during tuning and always found approximately the same amount of fuel in there. This indicates that the floats are doing their intended job. I don't know how else to diagnose this short of replacing the floats. This is not that easy as they don't seem to be sold any longer. Is the "black type" the hollow air filled kind?
Heavy floats would tend to make it flood out. As they become more fuel soaked and heavier, the level has to get higher to shut off fuel. You could re-adjust them, but the same thing would happen over time. If you could fins the proper type of foam, I guess you could carve new ones and replace them on the old yoke, or fabricate some from sheet brass. Just depends on how much work you want to do.
I still say you are the king of photo posting here! I've been following the thread just to see the photos you post of the work along the way. May come in handy some day!
Good luck and have fun,
Dan McEntee
Thanks for the input Dan! I think I addressed the issue of the float position earlier. Have a look at the carb after adjustment:
(http://i1341.photobucket.com/albums/o746/andreas_g_piepke/Penton/100_4199_zpsmjs03wkn.jpg)
I set the floats at a slightly upward angle. I determined the angle such that the desired fuel volume of 40 ml is in the float when the float needle shuts off and not such that the floats are parallel to the carb body. This method allows fuel level adjustment independent of the buoyancy of the floats. I think this is a good method, however, there seems to be no data out there to tell me what a good amount fuel in the bowl is. The carb is not flowing over so I think heavy floats submerging into the fuel too deep isn't a problem.
I really appreciate the input!
Andreas
Throw that float in the trash and don't think twice about it! Send me your address and I will ship you a good used black one. The float should be level just as the lever contacts the spring loaded pin on the float needle, not with the full weight of the float resting on the needle valve, which would actually depress the spring loaded pin into the needle giving an incorrect setting.
[email protected] Mike
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R
Thanks Michael, this sounds like a great suggestion! I just sent you an email.
Cheers
Andreas
As Mike says the float should be un-weighted when setting. Put the carb on it's side & it should be level just as the needle touches it's seat.
Also - in the pics above the slide on the right looks worn out. Bings were famous for having "soft" slides. As they wear they flop around forming the oval shaped ridge that you see in the pic, allowing air to leak around the slide. In worst case scenarios the slide will eventually jam partially or wide open.
_____________________________________________________________________________________
"We the willing, led by the unknowing, are doing the impossible, for the ungrateful. We have done so much, for so long, with so little, that we are now qualified to do almost anything, with nothing."
1972 Penton Berkshire 100
1983 Husqvarna 250 XC
2011 Jayco 31.5 RLDS
2009 Chevy 2500 HD Duramax
Float is shipping to you today. Another thing to make sure is that the float pivot pin does not have any burrs on it that could cause erratic function. If it feels rough, sand it with some emery paper to smooth it out. Mike
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R
Thanks a lot! I'll let you know once I received the part. I inquired at Bing about the availability of a type-0 slide for my carb, let's see what they have. I also asked for info regarding the location of the custom seat of my carb, relative to the float needle position of a standard carb of this type. I'll condition the pin that seems like a good idea.
Cheers and thanks again!
Andreas
Ok, I can't help myself from checking out this thread every once in a while. 4 pages and nearly 3000 views on this subject has to be a new record.
What exactly is a "custom" float seat? On page 2 of this article, it looks like a Mikuni float seat. If so, I would pitch that and get the correct seat and new needle from Bing. Bing carburetor = Bing parts. 12 different combinations of components isn't going to help you until you fix the float situation. Positively gorgeous photos. But the picture of the upside down carb and your jets doesn't show us (me) anything. You have to lift the float and slowly let it drop until the tab just touches the pin on the float needle and see where you're at. Level is a good starting point. Also, stick to the slide that belongs in your carb for your bike. In my opinion, your slide looks fine. I've run slides much worse looking than that with smiles in them and it had no effect on how the bike started or ran. A new one just makes the bike run better and crisper.
I hope I don't come off as a smart alack. It could just be my New England, get to the point, upbringing. Or my Dad's "I broke it, let's fix it". mentality. And somehow we always did.
Gordon,
This other thread explains what Andreas has gone through with the needle seat which was modified by Bing to fix his previously modified carb. Mike
http://pentonusa.org/forum/topic.asp?TOPIC_ID=15762&whichpage=3&SearchTerms=bing%2Cneedle%2Cseat
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R
Thanks Mike,
I must have missed that part of the saga.
Bing, pushing Mikuni parts, and fixing their own product with another companies hardware. First I've heard of that tactic. At least from them.
Not really! Some unknown previous owner had modified the the Bing carb with a Mikuni float needle. That individual drilled the original seat away, opened the hole and equipped it with a thread to accomodate the Mikuni part. I didn't even realize this mixup until people on this forum identified the components for me.
The needle was leaking and there seemed to be no way to get this fixed. I sent the carb to Bing and they were nice enough to custom build a new needle seat and fit it into the carb body so I can use an original new Bing float needle with Viton tip. They figured out how to do that, hand made a new float needle seat and installed it into the old carb. All of that for very reasonable price. So the Bing people went out of their way to make a 40 year old product useful for their customer. I was quite impressed by this customer service I have to say!
Cheers
Andreas
Hi POG,
Below find a picture of my new carburetor parts, acquired in response to your feedback:
(http://i1341.photobucket.com/albums/o746/andreas_g_piepke/Penton/100_4218_zps30eki9rx.jpg)
I got a new (not quite new but in good conditions) set of black floats from a friendly POGer! People had pointed out that my original size 0 slide (right in the image) shows wear. It indeed does. If one touches the engine side of it, it has a perceptible step. I purchased a new size 5 2 slide (I posted an image of the original part earlier in this string) but found it has only a 4 mm high cut-out while the original slides cut-out is 7 mm. Test running with the 5 2 slide indeed showed very rich mix, a wet plug. Correspondence with Bing actually revealed that my Bing 54 2/36/102 carburetor, when installed on KTMs or Pentons, was equipped with a size 1 slide. I further understand that a size 1 slide should have an 8 mm cutout. In response to that I machined the cutout to 7 mm to match what I had. It is interesting that the size 5 2 slide has a different inner rim height. However, when measuring how far the needle sticks out below the lower edge I get 43.1 mm for both slides. I conclude the needle position is equivalent on both slides. Another difference is that the bottom of the original 0-slide is closed where the choke slot is, my new 5 2 slide is open. I'll need to see whether this makes a difference in air flow.
The Bing people where also nice enough to tell me that for correctly set floats the fuel level in the bowl needs to be 1/2" below the upper rim. This constraint will now allow me to check correctness of the float position setting, independent of assumptions on the correctness of the float needle's location.
Last week I made another test run video: https://www.youtube.com/watch?v=NQYNQS5UYlE
The bike certainly runs better than before but still not satisfactory. I'll try out the new floats and slide.
Happy Easter to everybody on the list!
Andreas
I noticed that when starting the bike you did not hold the tickler down near long enough for the fuel to overflow the bowl vent lines. With a cold engine, hold the tickler down 3-5 seconds until you see fuel dribble out of those lines and it should start in a couple of kicks. Mike
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R
Will try next time after putting the new parts into the carb. Maybe I should try to replace the 40 pilot jet with a size 50 exemplar (was initially installed).
Thanks for sharing your observation!
Andreas
P.S.: One more question: what percentage open do you hold the throttle when attempting to start the engine?
None. Throttle closed until it fires. Opening the throttle defeats the choke operation. Mike
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R
Hi All,
I installed a new modified slide, and the new black floats. Initially this put me back to square one: an overflowing carb when running the engine. Taking the carb back off revealed: the little safety wire (very stiff) on the tickler was a bit long, rotated upward due to the engine vibrations and then held down the floats. I cut the wire shorter and this fixed the problem.
After fixing this issue the bike certainly now runs better than ever before. It is till difficult to start and seems to kick back after I kicked it over a number of times. I have already taken the ignition point back to 2.25 mm before TDC.
I posted another test run video on YouTube and asking for you input:
https://www.youtube.com/watch?v=tp1zKGhN6sg
The engine certainly now runs and the bike accelerates alright. However, I am unsure as to the engine performance. Judging from the rate of rise of the revs is this a reasonable engine performance? I don't seem to be able to make the front wheel lift off. I expected a little more "pull".
The image below shows a 1981 KTM 250 GS I had rebuilt from three box bikes in the late 1980-ies (with me an my late dad). That bike lifted the front wheel in second gear without problem. Do I need to fiddle more or is this "good running"? And Mike: my carb doesn't have a choke.
(http://i1341.photobucket.com/albums/o746/andreas_g_piepke/Penton/img002_zpsgoxnqm7u.jpg)
Cheers and happy Easter for everybody
Andreas
Well it sounds like you are definitely making good progress. Really hard to tell by the video sound, but sounded pretty clean. Since this is a "new" engine, I would proceed with caution from this point forward until you get some time on the bore and rings to let them seat properly. Have you checked your plug recently? Keep a close eye on it while you fine tune things. In this day and age with the laser temp gauges, I wonder how useful it would be to shoot a temp reading on a known, good running 250 to see what the temps are at the exhaust right near the cylinder? This might be a good way to help judge lean or rich.
As you get closer on the carb settings, you may find that you have to tune the Super Trapp silencer also, more plates, less plates, looser night, or tighter nut. I don't have a lot of experience with these, and may be putting one on the 400 I'm trying to finish up and would like to here what others think on this.
As as throttle on start up, I agree with Mike, especially since you have the Bing with no choke. Tickling the carb makes it over flow. Some goes into the engine, some flows out of the carb. Some engines like to be almost flooded when starting stone cold, and I'm guessing that you might not be tickling it long enough on a cold start. I keep the throttle closed, as this lets the slide block off the intake, and helps pull fuel through the idle jet. Cracking the throttle greatly lessens the effect. You had mentioned ,maybe trying the next richer idle jet, and you may want to do that. If you have to close the air adjusting screw to less 3/4 of a turn to get it to idle at all, that may be an indication also. Make sure you get the engine to operating temperature when testing out all carb changes also. Cold starts are just one of the things you have to figure out for each bike.
You have the internal flywheel motoplat on your bike, I think also, don't you? I think I saw that in one of your previous threads. That makes a big difference in how an engine responds and performs also. It will work hand in hand with the pipe/silencer combination.
You certainly are being very thorough and methodical in your approach to solving your problems. And your pictures and videos are very helpful and will be a good record that will help others as they go through the same process, like ME!
Good luck with the rest of the process,
Dan McEntee
PS to add;
I was taught to check years ago the spark plug as follows: Find a place where you can run the bike out to full top end revs on as high a gear as possible. Preferably running toward your truck and tool box! When you hit top speed, pull in the clutch and hit the kill switch and coast to a stop, then check your plug. That will let you check the plug as it was performing at it's peak, and really see how it is on the main jet. Adjustments to the idle jet, needle and slide are transitional and shouldn't affect how the plug looks on top end, but will influence the reading if you let the bike slow down while running, idling and such. We have come to know these trial runs as "Rudder Runs" !
Yes, throttle closed until the bike is running. Starting involves pulling fuel through the idle jet, often referred to as a pilot jet, and if the throttle is open, this will not happen regardless of choke or not. Again, hold the tickler down until fuel runs out the overflow first to almost flood the engine, KTM engines like a lot of fuel to start when cold. Mike
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R
Hi Daniel and Michael,
Thanks for the useful suggestions. I'll try them out. Daniel, have a look at the first page of this string: the bike has an external fly wheel. I haven't tried to tune the super trap and doing so seems a good idea. I have already changed to a size 50 pilot jet. Today I tried flooding the carb to overflow and then attempted to start with a close throttle. This didn't work, the bike only started after multiple kicks with half open throttle. I'll try again. Maybe I need to flood even more.
Thanks again for your help on this!
Andreas
Size 40 to 50 jet is a big jump, combined with the extra fuel by holding the tickler down. 1st rule of thumb is to do 1 change at a time or you never really know what helped. A 45 with slightly less tickler would be my suggestion ultimately. Try less tickler before changing the jet first just for starting. Once fully broken in the bike should loft the front wheel in all 6 gears. Take it out in the country and ride it for 30 minutes in one ride after taking a full throttle spark plug reading to make sure its not lean, then re-evaluate your settings, and even do another full throttle test with a new plug. Mike
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R
I still think all of your problems are with the modified float needle and seat in your Bing. I am even more certain of that since the new floats caused the carb to work differently, which should not happen.
Brian
There was no problem with the new floats, the very stiff tickler wire (securing the seal plate on it) was too long and hung up when it rotated up. I think I fixed this issue. The bike definitely runs better now than before but just not really right yet.
Thanks a lot for your input!
Andreas
The tickler sticking is a common issue. I have a '77 Hercules 250GS that would never overflow when I depressed the tickler. It took a close inspection and measurement to show that it was never touching the floats. I ordered a replacement assembly from Bing International and it was the same length. I don't remember how I made the extension, but I did extend it and it worked properly, and combined with the choke made it a one or two kick cold starter. But then I ran into the same problem with the return spring sticking. Took a while to cure that but got it fixed. If your carb doesn't have a choke, it does make it a bit more difficult to find the right combination of what it takes to start cold, but is possible. My '75 250 Husky has a Bing with no choke and it requires quite a bit of fuel to start cold, and once it does fire, I sometimes have to depress the tickler to help things out if it's really cold outside. I'll be watching for how it goes from here for you. At this point I would try to get some easy break in time on the engine and get the rings seated and make subtle changes along the way.
Type at you later,
Dan McEntee
I had a 250 penton like yours. It took me a while to find what the bike wanted to get it to start. Sometimes it's the process you go through to start it. As said before, tickle it till gas runs out the over flow. I kicked mine through easily two or three times to bring gas into the cylinder. Then kicked it to start. Good luck, the bike looks great.
73 Jackpiner
73 Husky 360 WR/RT
76 Husky WR360
78 husky cr250
10 ktm 250xc
02 bmw r1150r
I think you have a compression or maybe port timing issue. Do have the original piston or is your deal a rebuild ?
Hi All,
Indeed i was suspicious abiut the compression myself. I measured the gas pressure and found 165 psi. I think this value is not unreasonable for a re-build engine. Or what pressure would you aim for? Doe this sound too low or too high? The piston is a forged Wiseco from AB. I am assuming it is correct and installed it as such. Maybe I'll measure the compression pressure again this weekend. I'll also try to change the number of disks on the Super Trap.
I'll try out different starting procedures. The before-last video I posted (the one showing the many start attempts) isn't even the whole story. I had to push the bike up and down a hill twice to get it running initially. After that I could kick start it but only with difficulty. The 1981 KTM GS I owned long time ago was difficult to start too.
Thanks for your ideas!
Andreas
If the bike still is hard to start with using the tickler until fuel runs out the overflow hoses, I suspect weak ignition. Did you sand the paint off the engine mount points on the frame and engine cases to guarantee a good ground? I always run a separate heavy gauge wire from the Motoplat stator plate to the ignition coil mount bracket to eliminate the need to remove paint from the frame and engine cases. You can run one directly to any point on the engine from the coil mount, but I prefer directly to the source...It also helps Motoplat life. This is the #1 reason for poor running and hard starting bikes, with the exception of carb jetting, of course. Mike
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R
Has a leak down test been done yet?
It helps to eliminate so many of the "what ifs".
Michael, you are spot-on, with the bonding jumper!
Tom
I would say 165 psi is quite good. I have seen as little as 90 psi actually run on some small bikes. The leak down test with either vacuum of pressure tests the whole engine including the crank seals. I'm sure the specs are here in the archives but from memory but when you completely block off the intake and exhaust, if it hold 5 psi for more than 5 or 10 minutes you are good to go. Some guys prefer vacuum, and the same thing applies, if it holds a few inches of vacuum for a certain length of time, you are good to go. If you build a lot of engines, the stuff to do the job is easy to make, and only requires one of those hand vacuum pump brake bleeders from Harbor Freight to supply the vacuum. You may know someone that has the stuff also. But I don't think that is the issue. I think you just need to experiment with starting some more. The weak spark could be a leading contender. Vance Smith here on the POG list and on the VINDURO list does a great job of rebuilding the systems and testing them, and I think he has even figured out how to convert them to 12 volts for the lighting circuits. But the simple grounding like Mike describes can work wonders also.
Keep us posted,
Dan McEntee
I re-read the post from the beginning, because I was sure I had mentioned the ground wire addition, and it was very early mentioned on the first page and Andreas had mentioned that the Motoplat was tested By Penton Imports and the magnets re-magnetized, but no mentions if the grounds were cleaned, and no mentioned was made if he did go ahead and install a ground wire, but stated he would after trying a new plug. A good spark to the eye is not necessarily a good spark under load. Mike
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R
Oops
I hate it when that happens, double oops!
Hi All,
I do see a spark when I remove the plug. I didn't add a current return cable yet but did measure the resistance from the coil mounting to the engine when Michael pointed this out. I found good continuity then. The coil mounting tabs are not painted and the engine mounting bolts are all new and not corroded. Perhaps at this point I should follow Michael's advice, it's easy enough to do and eliminates one uncertainty. Yes indeed the ignition was load tested and the fly wheel re-magnetized. The ignition itself should be in good shape. I also have a new NGK spark plug of the recommended type.
For this vacuum test is there a description of the procedure somewhere? Do I need to take the carburetor and exhaust off for this so I can seal them?
I just read through the new thread on Super Trap exhaust. I'll certainly try to reduce the number of disks from now 7 to 4.
Just to be clear, I am battling with two different but perhaps related problems: (1) difficulty starting the engine, (2) low engine performance. This thread of posts kind of mixes these two issues.
Thanks for your input!
Andreas
HIGH ANDREW, My x wife just told me the reason she left me was because I did not have any SPARK left to kick it hard ENOUGH, TO GET IT STARTED,MAYBE GIVE THAT A TRY,THANKS JAKE
Andreas,
I feel you are not understanding the grounding of the ignition on the Penton.
The bolts have nothing to do with the ground except to keep the engine tight in the frame. The ground is between the inside of the frame mounts to the outside of the engine cases, and the coil mount to the mounting tab on the frame. Unless you have physically ground off the paint from the inside of those mounts and also on the engine mount bosses, you do not have proper ignition grounding. Period.
Do yourself a favor and install the ground wire from the coil mount bracket, (sand the connections to shiny metal) and run the other to a clean shiny metal point of the engine. you can always run it to the actual stator plate later to even improve the path. Then ride the bike and see if there is a difference with no other changes. It doesn't matter that the ignition is tested or you see a good spark. Mike
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R
As Michael said, just because you can see a spark it means very little. In A&P school we would test plugs that looked fantastic till you added a bit of cylinder pressure and watch them go dead. Same with coils.
Add the jumper.
Tom
I have some experience with testing under vacuum, but with these I prefer to test under pressure. It exposes the components (seals and such) too the same loads that occur under normal operation.
Perhaps this will help.
FYI, 3-5 psi will usually do the trick.
https://www.youtube.com/watch?v=zdq7NRcUIp8
Tom
Hi All,
Today I heeded Michael's words and installed a ground line from the coil to the engine:
(http://i1341.photobucket.com/albums/o746/andreas_g_piepke/Penton/100_4235_zpsun6k8hm8.jpg)
The copper braid gives a very low resistance current return now (verified with an ohmmeter). Michael I admit it: the engine does start easier now! Thanks for your suggestion.
One down, one to go: the engine still runs weak. I changed the number of disks in the Super Trap from 8 to 4 and found that the engine runs worse. So I will go to 6. By now I tried just about anything to get the engine running well but without real success. I probably will have to do the leak test describer in this thread. However, I don't have the tools and will have to rig-up a pump with pressure gauge (have that). I will also need to find appropriate plugs to block inlet and outlet, I don't have those. If this doesn't work then I'll probably have to take the engine back out and apart. I hope I won't have to do that!
Thanks for all your guidance it certainly helps!
Cheers
Andreas
Andreas, you've certainly been very methodical in your approach and have received a lot of good advice. By no means am I an expert builder or rider, but something in your video test caught my attention. It could be simply the sound and method of your shifting, but there were several times when your engine noise sounded like a slipping clutch. A slipping clutch would definitely keep the engine from performing properly. My 250 has a ton of acceleration and can lift the wheel in several gears.
Again, it could have been your shifting style (and using the clutch) but it had that sound. Also, I'm no expert at adjusting the Penton clutch, so I can't give advice on that. I just cringe at the thought of you pulling the motor apart without inspecting that option. How do you feel the clutch set-up is?
Mick
Hi Mick,
I don't think the clutch is slipping. I gave plenty of play to the mechanism, to a degree where I need to elevate the revs when engaging first gear to prevent the engine from dying. I did this exactly for the reason you mention: see whether the clutch is slipping. There seems to be no relation between test running the bike with more or less clutch play. The thought of taking the engine out again makes me cringe too! I certainly hope it won't be needed.
Thanks for sharing your observation with me
Andreas
To plug the exhaust and the intake, just go to the plumbing department of the hardware store and look for expandable rubber plugs in the size you need. You are only talking about 5 psi or so for this application so mo real need for anything more. Auto parts stores carry them also to replace freeze plugs. I even made one out of rubber hose and a carriage bolt one time to make a drain plug for my '75 Husky after the threads stripped out for the stock drain plug!
I'll be watching for updates and improvements.
Type at you later,
Dan McEntee
Hi All,
I do see a spark when I remove the plug. I didn't add a current return cable yet but did measure the resistance from the coil mounting to the engine when Michael pointed this out. I found good continuity then. The coil mounting tabs are not painted and the engine mounting bolts are all new and not corroded. Perhaps at this point I should follow Michael's advice, it's easy enough to do and eliminates one uncertainty. Yes indeed the ignition was load tested and the fly wheel re-magnetized. The ignition itself should be in good shape. I also have a new NGK spark plug of the recommended type.
For this vacuum test is there a description of the procedure somewhere? Do I need to take the carburetor and exhaust off for this so I can seal them?
I just read through the new thread on Super Trap exhaust. I'll certainly try to reduce the number of disks from now 7 to 4.
Just to be clear, I am battling with two different but perhaps related problems: (1) difficulty starting the engine, (2) low engine performance. This thread of posts kind of mixes these two issues.
Thanks for your input!
Andreas
HIGH ANDREW, My x wife just told me the reason she left me was because I did not have any SPARK left to kick it hard ENOUGH, TO GET IT STARTED,MAYBE GIVE THAT A TRY,THANKS JAKE
Andreas,
I feel you are not understanding the grounding of the ignition on the Penton.
The bolts have nothing to do with the ground except to keep the engine tight in the frame. The ground is between the inside of the frame mounts to the outside of the engine cases, and the coil mount to the mounting tab on the frame. Unless you have physically ground off the paint from the inside of those mounts and also on the engine mount bosses, you do not have proper ignition grounding. Period.
Do yourself a favor and install the ground wire from the coil mount bracket, (sand the connections to shiny metal) and run the other to a clean shiny metal point of the engine. you can always run it to the actual stator plate later to even improve the path. Then ride the bike and see if there is a difference with no other changes. It doesn't matter that the ignition is tested or you see a good spark. Mike
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R
As Michael said, just because you can see a spark it means very little. In A&P school we would test plugs that looked fantastic till you added a bit of cylinder pressure and watch them go dead. Same with coils.
Add the jumper.
Tom
I have some experience with testing under vacuum, but with these I prefer to test under pressure. It exposes the components (seals and such) too the same loads that occur under normal operation.
Perhaps this will help.
FYI, 3-5 psi will usually do the trick.
https://www.youtube.com/watch?v=zdq7NRcUIp8
Tom
Hi All,
Today I heeded Michael's words and installed a ground line from the coil to the engine:
(http://i1341.photobucket.com/albums/o746/andreas_g_piepke/Penton/100_4235_zpsun6k8hm8.jpg)
The copper braid gives a very low resistance current return now (verified with an ohmmeter). Michael I admit it: the engine does start easier now! Thanks for your suggestion.
One down, one to go: the engine still runs weak. I changed the number of disks in the Super Trap from 8 to 4 and found that the engine runs worse. So I will go to 6. By now I tried just about anything to get the engine running well but without real success. I probably will have to do the leak test describer in this thread. However, I don't have the tools and will have to rig-up a pump with pressure gauge (have that). I will also need to find appropriate plugs to block inlet and outlet, I don't have those. If this doesn't work then I'll probably have to take the engine back out and apart. I hope I won't have to do that!
Thanks for all your guidance it certainly helps!
Cheers
Andreas
Andreas, you've certainly been very methodical in your approach and have received a lot of good advice. By no means am I an expert builder or rider, but something in your video test caught my attention. It could be simply the sound and method of your shifting, but there were several times when your engine noise sounded like a slipping clutch. A slipping clutch would definitely keep the engine from performing properly. My 250 has a ton of acceleration and can lift the wheel in several gears.
Again, it could have been your shifting style (and using the clutch) but it had that sound. Also, I'm no expert at adjusting the Penton clutch, so I can't give advice on that. I just cringe at the thought of you pulling the motor apart without inspecting that option. How do you feel the clutch set-up is?
Mick
Hi Mick,
I don't think the clutch is slipping. I gave plenty of play to the mechanism, to a degree where I need to elevate the revs when engaging first gear to prevent the engine from dying. I did this exactly for the reason you mention: see whether the clutch is slipping. There seems to be no relation between test running the bike with more or less clutch play. The thought of taking the engine out again makes me cringe too! I certainly hope it won't be needed.
Thanks for sharing your observation with me
Andreas
To plug the exhaust and the intake, just go to the plumbing department of the hardware store and look for expandable rubber plugs in the size you need. You are only talking about 5 psi or so for this application so mo real need for anything more. Auto parts stores carry them also to replace freeze plugs. I even made one out of rubber hose and a carriage bolt one time to make a drain plug for my '75 Husky after the threads stripped out for the stock drain plug!
I'll be watching for updates and improvements.
Type at you later,
Dan McEntee
Hi Penton enthusiasts,
After some time away from this I finally rigged up a pressure test for my 1973 KTM engine. Getting parts that work and are gas tight was an ordeal in itself. I tried 5(!) different pressure hoses before finally arriving at the on shown in the image below. I am using a valve opener hose which has a female NPT thread on one end and an appropriate spark plug connector with rubber o-ring on the other.
(http://i1341.photobucket.com/albums/o746/andreas_g_piepke/Penton/100_4422_zps6rwil3mn.jpg)
After pressurizing the engine to 5 psig I see the pressure dropping (exponential in time as expected) at a rate of about 0.0044 psi/s. This means that the pressure halfs in about 2 minutes. I sprayed the engine with soap water but can't find a leak. I guess at this point I have to conclude that (a) the engine is not gas tight, and (b) I have to take it out of the frame for closer inspection. I hope I don't need to dismantle it altogether! Any more ideas for what to do short of taking the engine out?
Cheers
Andreas
Definitely a leak somewhere, it should hold pressure longer than that.
Brian
Pull the mag case off and the flywheel and ignition and spray the crank seal and the flange it's in with soapy water and see if maybe the leak is there. after that it may be the crank seal on the clutch side. Also spray the bottom of the engine and check the center case gasket. Good luck. It's a pain to go through this after all your great work. The bike looks awesome.
73 Jackpiner
73 Husky 360 WR/RT
76 Husky WR360
78 husky cr250
10 ktm 250xc
02 bmw r1150r
Hi All,
So Brian and Dale I've done what you said. After taking the magnet, ignition, and ignition holder off this is what I found:
(http://i1341.photobucket.com/albums/o746/andreas_g_piepke/Penton/100_4446_zps0m8fsdy6.jpg)
There is oil on the seal holder. There was also a little oil on the back of the ignition holder. I pressurized the engine to 5 psi and found a tiny leak at the crank seal:
(http://i1341.photobucket.com/albums/o746/andreas_g_piepke/Penton/100_4447_zpsbm9gdc8w.jpg)
These are tiny bubbles, the leak is probably quite small. This side is easy to fix so I'll go and replace the seal and the gasket under the seal retaining plate. I hope that'll cure my problems! Is there any way to get to the gasket on the left side without taking the engine apart? I don't even know how to test the left side seal. I drained the transmission fluid, it doesn't smell like gasoline but not like ATF either. I cringe when thinking that I have to take the engine apart just to get to the seal.
Thanks for your input, keep sending ideas!
Andreas
Andreas,
That may be the problem. I think if it were the trans side, it will suck trans oil in. It would show in the exhaust by showing more smoke than normal. I know the 250 I had was hard to start. Sometimes it's the routine as much as the bike. I kicked it slow thru 2 or 3 kicks and then kicked it to start. It's all a learning process.
73 Jackpiner
73 Husky 360 WR/RT
76 Husky WR360
78 husky cr250
10 ktm 250xc
02 bmw r1150r
I think you found your problem.
Brian
I think I'd lead it out behind your house, and when it's not looking, hit it with a shovel.
To check the other side seal, stick the crankcase filler vent hose in a container of fluid then pressurize the engine. If you see any bubbles, there is a leak.
Mike
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1978 KTM 250'S
1975 Can Am 175 TNT 250 conversion
1976-78 125-400 RM's & 79 PE250 Suzuki & 2012 DR650
2007 CR125R Honda
1977 MC250 Maico
Gordon, does that scenario usually follow with a story to the kids that their favorite pet must have ran away?
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1978 KTM 250'S
1975 Can Am 175 TNT 250 conversion
1976-78 125-400 RM's & 79 PE250 Suzuki & 2012 DR650
2007 CR125R Honda
1977 MC250 Maico
Thanks for the tips! I think I will pass on the one requiring the shovel. The test with the bubbles is a great idea. I'll try this should the engine not be leak tight after replacing the right side seal.
Andreas
Hi All,
So I took the seal holder off today and inspecting the seal showing the leak. The seal seems to be in good order, I cannot see an obvious problem with it. I took photos of both sides of the seal and seal holder:
(http://i1341.photobucket.com/albums/o746/andreas_g_piepke/Penton/100_4452_zpsrmbhxxb2.jpg)
(http://i1341.photobucket.com/albums/o746/andreas_g_piepke/Penton/100_4453_zps6iz3fqh8.jpg)
The manual gives no value for how far to press the seal in. I choose a location relatively far out so the lubrication channel stays open. Have a look at the crank, the seal seems to sit at the far end of the sealing surface.
(http://i1341.photobucket.com/albums/o746/andreas_g_piepke/Penton/100_4457_zpsddrkilll.jpg)
I am wondering whether I should simply press the seal a little further in and see whether or not this fixes the problem. I would appreciate any guidance you guys can give me on the proper position of the seal. I don't want to ruin the crank bearing by obstructing too much of the lubricating channel.
Thanks!
Andreas
P.S.: This is irrelevant for this string and the POG but for your enjoyment a picture of the other project I am working on, a 1973 Norton Commando with an electrical issue.
(http://i1341.photobucket.com/albums/o746/andreas_g_piepke/Penton/100_4451_zpsjjxzkijz.jpg)
Beware of old NOS seals found on eBay, sometimes they are not worth buying due to age and stiffness. NOS in this case means Not Often Sealing, lol. Get a new one from Al Buehner or match it up at a local parts store or bearing supply house with a fresh new one. Not sure on the positioning, but the as installed pics look like it should go in a little farther and polish up the crank surface and inspect for tiny slight rust pitting. Always apply a little sealant around the outside of the seal where it presses into the retaining plate. Mike
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1978 KTM 250'S
1975 Can Am 175 TNT 250 conversion
1976-78 125-400 RM's & 79 PE250 Suzuki & 2012 DR650
2007 CR125R Honda
1977 MC250 Maico
Thanks Mike, I'll do that. The seal in the pictures was actually purchased new from Al. I see no problem with the seal itself.
Cheers
Andreas
Again, the photos are outstanding! Almost like being there! As it sits now, it's not too difficult to do as you are thinking, push the seal a little further into the holder and re-pressure test it. The lip on the seal may not be seating correctly when it is. Might be possible to measure where the "sweat spot" on the crank shaft is by measuring off machines surfaces on the case and seal holder. Try and mate up the lip of the seal with the wear surface better. If the outside edge of the seal blocks the lubricating channel at all, perhaps it can be snipped a bit at that point and opened up?
Like others have said, I think you found you problem.
Good luck and keep us informed. Too bad you have had to do all this extra work, but this thread has been very informative and instructional.
Thanks a lot,
Dan McEntee
Andreas,
If it were me, I'd remove the seal to make sure the seal plate surface doesn't have any corrosion pits. I had that happen to me on an engine with a brand new seal which looked fine until I removed it. The corrosion pits were so deep that the air was actually escaping around the outside of the seal and not between the lip and crank journal. Can't hurt to look.
Dave McCullough
Good points. I'll get a new seal and a new gasket (already ordered) and then leak test the engine again. I'll lightly polish the crank sealing surface. The leak is very small and might indeed be due to some subtlety.
If fixing the air leak doesn't improve engine performance then I'll need to understand whether or not the clutch slips under load. Someone already pointed this out in this string of posts. I should probably start a new post if I have to do this.
Cheers and thanks for your continued interest!
Andreas
P.S.: Dave, I actually made a photo of the seal holder before installing the new seal in May 2014. The sealing surface didn't show any corrosion, have a look:
(http://i1341.photobucket.com/albums/o746/andreas_g_piepke/Penton/100_3533_zpswrzjfwba.jpg)
I always use a smear of gasket goo on the outer edge of the seal when pressing it in to ensure a sealing surface when using the steel edged seals.
And yes, i would be pressing the seal in further to ensure both lips are on the flat surface.
When installing put a smear of a molykote o-ring or seal grease to the lip of the seal.
Regards,
Adrian Goold #101
http://www.ozktm.com
(http://i1089.photobucket.com/albums/i342/ozktm/1974%20KTM%20250%20Penton/1BB79418-1F02-412C-9EF5-67C029A9A961-1733-000002851414FCA5.jpg)[/URL]
'73 175 Rebuilt|2x'74.5 250 |'74.5 400 Restoring|2 x'76 MC5 250 |'76 MC5 400 |'78 250 in pieces|'81 250 | '81 495|74 CZ 250|
Your trouble is that the seal is to far out. The seal should be flush to the back side of the plate.
Adrian, your bike looks great! Does it run as good as it looks? I can try a seal compound next time. G. Ellis thanks for the advice regarding seal location. I didn't find instruction in the manual. When pushed the seal all the way back, the steel rim of the seal will obstruct the lubrication channel. That's a worry I guess. Do you cut or file a part of the rim away?
Thanks for the advice!
Andreas
There is plenty of room for oiling. Do not cut on the seal. Oil will get by on top of seal to the main bearing. I don't thing that anything is wrong with the seal. The seal is just not far enough back.
I agree with Gary on the seal. As long as the rubber on the seal is soft and pliable, it should be good.
OK, thanks for the input. Now that I've taken the part off I'll put in a new seal anyway. I'll follow your advice.
Thanks for your input
Andreas
I agree with everyone saying do not use NOS seals. They could be stiff, and most are only a single lip seal.
The seals that I provide for the KTM engines are Viton double lip seals and I have to have these made special order because the bearing houses do not stock them.
The double lip also helps as double protection against leakage in case there is wear groove in the crank pin from the old single lip seals.
Alan Buehner
Lots of great information here. Reminds me that I don't know what I don't know.
Did Andreas get the Penton to finally perform to his expectations?
RP
Yes, it does run now. Have a look at a short video I recently posted on YouTube:
https://www.youtube.com/watch?v=w9Hzin_caXk
The tank has been painted by now too. I posted some new pictures in a posted called "GS conversion". Post some pictures of your bike and your work on it too!
Andreas
Congratulations!
This 8 pages of technical and troubleshooting data should be a must-read for all Penton "newbies" like me. Gotta have webmaster Dale weigh in and start a best-of-the-best area that novices can tap into and read this type of discussion. I found it in a search for "petcock" as I was looking for a replacement(s)
RP