Greetings,
Last weekend, after a couple of years of restoration work I started my 72 Jack Piner for the first time. Idling it runs fine, revving it in neutral runs fine. When I take off though, it bogs down when I give it throttle, eventually loading up and stalling. Sometimes this happens in 1st, sometimes I make it to 2nd or 3rd. But it always seems to be happening. The engine is completely rebuilt (crank, all bearings, piston rings ect), brand new 30MM type 84 Bing carb. My initial thoughts were that this was somehow related to the clutch, as I noticed that the clearance at the actuator was only 1-1/4" in lieu of the 1-5/8" to 1-3/4" speced (my thought process here was that it was possible the clutch was not completely disengaging). So I changed out the clutch springs, push rods and the little pin that is in the barrel of the clutch actuator. After putting everything back together the clearance at the clutch actuator now measures 1-3/4" and the clutch snaps out like it should. But I still have the same problem. I can leave it idling forever or rev it up in neutral. But when I take off I go a short distance it bogs down and pukes out. If anyone has any ideas or advice on that to check next I would really appreciate hearing them.
Thanks in advance,
KD
Kevin J. Donovan
Foster, Rhode Island
72 Jack Piner (My Ride)
72 Six Day (Wifes Ride)
I would take it's flooding out. If your timing is spot on, it's time to check the carb for proper jetting. Air filter clean, exhaust pipe clear?? Check the easy stuff first.
Thrownchain,
I have checked the carb appears good, the air filter is new and not overly oiled. I rebuilt the pipe, but I will try running it without the baffle and see if that makes a difference.
Thanks,
KD
Kevin J. Donovan
Foster, Rhode Island
72 Jack Piner (My Ride)
72 Six Day (Wifes Ride)
KD,
Just have start with take off the filter and try it. If that doesn't help try it without the pipe. You see where I am going...just eleminate one thing at a time. Without being there in person I initially would think the bike needed a bore job because it is fine without a load, but since it is a fresh bore that should be thrown out. Just for grins I would check compression unless it obvious the compression is high just by how hard it is is to kickstart.
Next I would be contimplating anything that has drag on the engine once you put it gear. Got to go, but I have about 10 hours of windshield time today to think about it. Hopefully by then we will find out it has a weak spark or only needs a new spark plug or plug cap[:p]. Oh, be sure to check all the grounds especially if you powdercoated the frame. Good luck.
Ron Carbaugh
Did you say the Carb was brand new or was it rebuilt.... On a Bing carb the needle jet and the jet needle wear pretty fast, was all the jets replaced? Are you sure that the jets are stock sizes.. If these are not in good shape it could be the problem and when it comes to jets, you can not tell if they are bad, the only way to know for sure is to replace them. you said it idles nice so I do not suspect the pilot jet and the main does not really wear that much and besides it would not effect what you are experiencing so that is why I suggested the needle assmebly. If you have any questions about proper jets for the bing, give Bing International a call, they have been very helpfull in the past for me.
Does it start easy or does it take more than several kicks to get it started, What I quess I am getting at is that if the timing is spot on and it starts easy then it is probably not the ignition, thought I have seen coils that seem to work fine but in reality have an internal short and it does not show up until you put them on a load. I had that happen to one of my bikes earlier this year at first I thought it was a ground problem but after cleaning everything it changed nothing, I knew the carb was fine because I had cleaned it and up til then had run good I exchanged the coil and wham! The problem disappeared. I put it back on and there it was again.... Good luck!!
Thom Green,Still crazy after all these years!
76' 250 MC5 (orginal owner)
75' GS400 (project bike)
72'sixday (project bike)
Didn't think of that, could be electrical. Check plug, coil, cap and condenser if there is one.[ not really up on 175 ignitions ]
Using fresh fuel? I tried some old premix in my 200 and 175 this season and had trouble similar to what you are having until I got fresh hi test in them. Stuff would'nt run in my weed eater either.
GC
KD,
One other thing to try......
I had a Hodaka that did the same thing. Rev'd out on the stand just fine, heat cycled it several times over two days and it never fouled a plug or stumbled. As soon as I jumped on it and tried to ride it up a steep hill to the driveway it would always bog and die.
Finally ended up going down one size on the main jet (Mikuni 34mm) and it got better. Ended up two sizes down on the main jet, but it finally ran good.
Andy
#14u MOVMX and AHRMA
75 Jackpiner
92 KTM 300
70 Steeltanker
Kevin how long are you letting it warm up before you ride it? Go back and look at some of Larry Seale's old posts I think he had a similar problem. Just don't do like Larry and ride it down a hill keep on the flat. Much easier to push back home.
Rod Whitman
1972 Six Day (Rider)
1972 Six Day (Project)
...........KJ,if the ignition is good you need to have this jetting:slide #1,slide needle #1 in middle groove,main jet #150-155,needle jet #2.76 or 2.80,pilot jet #35-40 and the new type atomizer #40-404..........the atomizer #40-404 is the one with one small air hole,look down the air bell side in the bottom air passage to see if you have this type,I have soldered shut the 4 large hole type holes and drilled one small .062 hole when the 40-404 was not availible.............
Please don't laugh at my comment, as this has happened. Are you sure that you have the choke in the proper position.
Paul
Rod, I'm still trying to catch my breath from pushing that sucker uphill all last summer [B)] . It turned out to be a bad coil, but I tried everything in the discovery process (except test drives on flat terrain :-((
Paul,
I was guilty of exactly that (choke on) on my '72 Jackpiner last winter. Thank God I don't chew gum!!!! LOL (although I will make the disclaimer that the picture in the '72 manual mislabeled a closed choke as being open).
I really should have used an alias the first year I was a POG member, so I could fly beneath the radar of my own goofiness.
KJ, sounds like an electrical problem to me, that only shows up once the coil heats up and comes under load. How long is the engine running before it bogs/dies?
Larry Seale
I choose to ride
I had a 77 400 doing pretty much the same thing one time. Turns out I assembled the carb wrong. I mistakenly put the needle clip inside the plastic cup....rather than under the plastic cup....this had the same effect as raising the needle a notch. I thought I'd never figure it out....
Check out the site below for an exploded view.
http://www.bingcarburetor.com/offroad/54x.html
Thanks for all the responses...Based on everyone's feedback I think I am narrowing this down a little...here is where I stand.
1) The carb is brand new (waited 3 months for this puppy, and Charlie at Bing did the jetting himself, so I am confident it was done correctly.
2) The choke is in the shut position (plunger down). I use a thumb lever choke in lieu of the one with the cable so I can see the exact position.
3) The fuel I am using is fresh 93 Octane (ethanol free) with fresh Spectro concentrate.
4) I have tried it with the air-cleaner removed, and had the same results.
5) Last night I pulled the baffle from the pipe and had slightly better results but still completely unsatisfactory.
6) I let the bike warm up at least 5 minutes before trying it.
7) The bike will run indefinitely at an idle by itself.
I have a spare coil in my box o parts that I am going to try tonight and I am going to check the compression this weekend after I make up a test kit. I am hoping it is not an issue with the bore, but at this point that's what my gut is telling me. When I had the cylinder done last summer it was by a one man outfit recommended by the local KTM shop (Razee's NK RI) and when I put everything together it all seemed snug. That being said, our 125 puts up more of fight to kick over than this does, but the 125 has a shorter kick starter too (less leverage). The one thing that I did do, that I wan never really comfortable with was to drill the 2, .060 lube holes in the front of the piston as repair manual and instructions from Wiseco recommended. It's been at least 25 years since I rebuilt one these but I never remember doing that in the past. If anyone has any other ideas I would be happy to hear them.
Thanks!
KD
Kevin J. Donovan
Foster, Rhode Island
72 Jack Piner (My Ride)
72 Six Day (Wifes Ride)
Kevin,
Did you powdercoat the frame? If you did you need to do a ohm resistence check to be sure that your ignition system has the proper ground (condinutity). I will be back at my shop/home tonight if you need to email me you phone number and I will try to help you. I hope this helps.
[email protected]Ron Carbaugh
Kevin,
Ron's suggestion about the continuity is valid, but you can't depend on a reading from a meter to tell you if you have a ground that is sufficient. Meters are usually only operating on 3 volts, where the Motoplat ignitions' grounds are carrying around 190 volts. If the meter tells you that you have some continuity, that won't necessarily carry the ground for the ignition system.
It is alwasy my suggestion that you scrape at least one engine mount on the frame and engine, free of paint, so you are absolutely sure that you have a sufficient ground.
Dane
Dane / Ron,
The frame is powder-coated. And now that I think about it, I am not all that confident that I have a good ground between the frame and the engine. I say this because my tail light only works intermittently; in fact the only time it worked was for a few minutes on Sunday while I was dinking around with the throttle cable. I'll start here tonight by running a test lead from the ground under the tank directly to the jug.
Thanks guys, I'll let you know how I make out.
KD
Kevin J. Donovan
Foster, Rhode Island
72 Jack Piner (My Ride)
72 Six Day (Wifes Ride)
KD,
Also make sure your coil has a good ground as well.
Donny Smith
KD,
Ron and Dane make a very good point about the grounding issue as a place to start searching. Having had the opportunity to help Larry troubleshoot his bike a little bit last summer, your problem sounds very similar to what his bike was doing. I even got a chance to push his bike across my fairly level front yard a couple times. Just wish we would have gotten the trouble solved before he had to push it up that darn hill so many times. One other thing I can of think since you said compression seems low. Did you get the deck height setting correct when installing the new piston ?? If you have too much deck height then compression would be low even with a new piston/ rings. Good luck and keep us updated on the progress.
Dave McCullough
Kevin,
Here's my 2 cents worth.
My first Penton was a brand new 1972 Jackpiner. Mine did exactly as yours is doing. It had the old black wire coil & motoplat. The dealer exchanged the motoplat and installed a red wire coil and that solved the problem. My question is... did you have the motoplat & coil tested when you did the restoration?
Guys,
Problem is not solved yet but I think I may be on the right track, here is where I stand.
After work last night I started checking out grounds. First I removed one of the engine mount bolts and ground the paint off the frame where the nut backs up against the frame. Next I removed the coil and where it bolts to the frame I removed some more paint where the nuts back up to the frame. Put things back together and started it up. The bike ran as it did in my earlier tests, but now it is not dying out completely, but I still cannot tach it up under a load. Additionally, the headlamp and tail lamp light are both now working, but both are really dim. This has me even more confused because this past weekend when the taillight worked for a few minutes it was extremely bright while the bike was idling. At this point I am now leaning towards this being an electrical problem, which is definitely not my specialty. I am guessing that I hosed up the wiring or the coil is bad. Part of the problem here is that I am using an aftermarket light switch which is nothing like one of the original dipper switches (which I was never able to locate). This switch contains a kill button, and lights off/hi-beam/lo-beam switch. Unlike the dipper switch though it only has one connection for incoming power. Below is a picture of the wiring diagram I made up using this switch and my existing motoplat.
[img][/c:\72wir.jpg]
(Hopefully the diagram displays below, I never posted a picture here) If anyone sees any glaring problems with diagram please let me know.
Also in response to Dave's question, regarding the deck height of the piston, I did check this before I put the head on and it was at 7MM. Randy asked if I had the motoplat tested during my restore and the answer is no. It was something that I was hoping was good, because the basket case I started with was retired due to a broken crank.
I will not get another chance to work on the bike until Friday. My plan is then to disconnect anything connected to lights and swap out the coil I have with a spare and give it another try. But as always if anyone has any ideas, I sure would appreciate hearing them.
Thanks Again,
KD
Kevin J. Donovan
Foster, Rhode Island
72 Jack Piner (My Ride)
72 Six Day (Wifes Ride)
Kevin,
Sounds like you are making progress. I agree with disconnecting the lights first since the switch is not original. The next step I suggest isn't a popular one, but itis necessary if you expect to ride this bike and not have future problems. I would take all the engine mounting bolts out and sand the inside of the engine mounting brackets to bare metal and put a electrical conducting grease (NAPA) and then bolt it back up. Next I would do the same to the coil mounting bracket. Then try the bike. If it still does light to the moon change the coil.
If the bike is working next check out all the grounds for the lights. We will wait for a report back so that the real experts on this site can get involved.
Ron Carbaugh
Kevin this is really coming from left field but is enough gas flowing to the carb? If the gas was just tinkling out it would get enough to idle ok but as soon as you started to ride it wouldn't keep up. Just a thought. Good luck.
Rod Whitman
1972 Six Day (Rider)
1972 Six Day (Project)
Kevin,
I don't mean to over simplify your problem, but I looked back through the posts, and I don't find anywhere that you have tried a new spark plug. Just because the plug fires at idle doesn't necessarily mean that it will fire under load. A crack in the ceramic insulator can cause it to misfire under load which generates higher combustion pressure (similar to a weak Motoplat spark). Certainly keep looking for ground problems, but a plug change is so easy it is worth trying. Good luck.
Nelson Lingle
Nelson,
I failed to post it here, but a new plug is one of the first things I tried.
Thanks,
KD
Kevin J. Donovan
Foster, Rhode Island
72 Jack Piner (My Ride)
72 Six Day (Wifes Ride)
KJ, I agree with firsturn, sanding off the paint on the outside of the motormount is a good start but really you should sand off the inside of the mount, the reason is that it provides alot better, more direct path for ground. With the outside of the motor mount, the path includes the bolt and washer, and it relys on the hole in the engine to creat the path to ground. I had never thought of using dyalectic grease before, but that makes sense to me... I will add that to my assmebly procedures.
Thom Green,Still crazy after all these years!
76' 250 MC5 (orginal owner)
75' GS400 (project bike)
72'sixday (project bike)
Thom,
I thought I said sand the inside of the engine mount? I don't normally sand the outside of the engine mounts because I have just spent $$$ to powder coat it and don't want it to look trashed.[8D]
Ron Carbaugh
Ron, you did say inside and with good reason:D
Thom Green,Still crazy after all these years!
76' 250 MC5 (orginal owner)
75' GS400 (project bike)
72'sixday (project bike)
How about running your ignition lead direct to the coil? Bypass the after market switch all together. This also takes the lights out of the mix. Possibility that the lights might have a short that's drawing power from the ignition? Is there a way to check ignition output to the coil??
Kevin: Instead of removing engine etc...try what all of my Pentons and Hondas had done before I ever rode them. Run a wire from stator plate to coil bracket. Make sure coil bracket does have a clean ground between it and a clean no paint frame mount hole. I also used to run a ground wire from there to the kill switch. You are not relying on frame bolts that corrode or steering bearings at this point. In your case to see if that is the problem you don't need to do the kill switchground now. The japanese always run ground wires to lights etc so there is always a good path for the electricity. If this doesn't work I agree with Ron and get another coil to try. Maybe you can borrow one. Ted
Guys,
Looks like my problem may be a compression issue. :( I just checked it and it's only 80 PSI. I need to know what the compression should be at for this bike? I can't seem to find this number anywhere.
Thanks,
KD
Kevin J. Donovan
Foster, Rhode Island
72 Jack Piner (My Ride)
72 Six Day (Wifes Ride)
It sounds like it is time for a new piston, rings and a bore job, I am not sure exactly what it should be but your Penton has a high compression ratio.... I believe it is 11:1 what that means is that it should have 170 Psi or so. That is really not the point though, 80 psi is really low, I am amazed that it even runs. I hate to even say this but, are you sure that your reading is accurate? Not that I doubt you or your tools but 80 psi is really low, I have had bikes with cracked rings that had more compression than that! It is time to pull the top end and find out what is going on.. I think you found the problem, It now makes perfect sense.
Thom Green,Still crazy after all these years!
76' 250 MC5 (orginal owner)
75' GS400 (project bike)
72'sixday (project bike)
KD,
Was just going back and reading all the posts again and something I noticed about the deck height. Your reply says you set it at 7mm. Did you mean you set it at .7 mm ?? If you set it at 7mm then that would explain the low compression.
Dave McCullough
It would take an awful lot a gaskets to achieve a 7mm deck height! I read that the engine was freshly rebuilt. Did you specify to the machinist what to set the piston to cylinder clearance? Gary Ellis pointed out to me when the 175 I bought in May with a fresh top end turned out to have a badly scuffed piston, that most machine shops are used to water cooled bike engines with much tighter cleannces than for an air cooled bike, and it ruined a brand new piston, but fortunately the cylinder is still OK to hone out to fit another NOS piston without having to rebore it. This time it should be done right! I would look through the intake and exhaust port and see if you can see whether the piston is scuffed like mine was, or smooth. Mike
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 250'S
Dave,
I meant .7 (left off the decimal point). Looks like it is back to square one for this bike. After coming up so low on the compression, I have already pulled the engine from the bike and tore it down. Needless to say I am a whole lot less than pleased with the guy who bored it for me. He came recommended by the local KTM shop too. Not really sure what the next step from here is. The piston I just pulled was 65.5MM and I am not sure how much larger I can go before re-sleeving. Thanks again for everyones suggestions which helped my track down this problem.
KD
Kevin J. Donovan
Foster, Rhode Island
72 Jack Piner (My Ride)
72 Six Day (Wifes Ride)
KJ,
can you measure the piston to cylinder wall clearance. You can use a feeler gauge to slide between the piston and the cylinder walls at 90 Degs from the wrist pin. Let us know what the clearance is. 65.5 is an .080 over piston . Thats a lot off the cylinder walls.
John D.
KD,
I thought it might be a typo on the deck height but just wanted to be sure. Sorry to hear about the poor machine shop work you had done. I had a similar experience with my Jackpiner earlier this year only mine was too tight and I ended up scuffing a brand new piston just like Michael described. Once you determine what the piston to wall clearance is let us know. If it's not too far out of limit then maybe you can send the piston to Swain Technology to have it moly coated. This will add about .0015" to the piston diameter and might get you back in limits again.
Dave McCullough
KJ,
can you measure the piston to cylinder wall clearance. You can use a feeler gauge to slide between the piston and the cylinder walls at 90 Degs from the wrist pin. Let us know what the clearance is. 65.5 is an .080 over piston . Thats a lot off the cylinder walls.
John D.
KD,
I thought it might be a typo on the deck height but just wanted to be sure. Sorry to hear about the poor machine shop work you had done. I had a similar experience with my Jackpiner earlier this year only mine was too tight and I ended up scuffing a brand new piston just like Michael described. Once you determine what the piston to wall clearance is let us know. If it's not too far out of limit then maybe you can send the piston to Swain Technology to have it moly coated. This will add about .0015" to the piston diameter and might get you back in limits again.
Dave McCullough