Can't get it running

[JP Morgen]

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!

[Andreas Piepke]

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

[SouthRider]

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

[Andreas Piepke]

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:



I installed it such that it aligns with the air channel shown in the picture below:



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

[SouthRider]

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

[Andreas Piepke]

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

[Dale Fisher]

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...

[SouthRider]

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

[Andreas Piepke]

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.

[Andreas Piepke]

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.


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

[Rocket]

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?

[Andreas Piepke]

The piston is installed the in the right orientation with the window toward the inlet, have a look:



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
 

[Daniel P. McEntee]

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

[Steve Minor]

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.

[t20sl]

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