engine won't idle unless moving forward

I bought a 1963 Peugeot 104. With some great help from Moped Army experts I cleaned the carb, cleaned the points, set the timing, cleaned the rust from the tank, put in an inline fuel filter, crossed my fingers, pedalled like hell, and shed tears of joy when she started up. I was like a little kid who had just learned how to ride my bike going around the block with a huge smile on my face. I got it up to thrity and things began to shake. Anyway that's the history. And here are my next set of questions.

When I get the engine started I must be moving, even if its at a crawl, at all times. As soon as I come to a stop, the engine is killed. Is there some adjustment I need to make to the centrifical clutch?

The shut-off screw connecting to the tank leaks like a sive when I unscrew it to let fuel flow to the carburetor. My guess is that it is an original part and the threads have worn over time allowing enough of a gap for fuel to leak out. How should I fix this? For now the short term solution has been to wrap some thread around it just to slow the leak.

My back brake doesn't work. The cable pulls on the disc but nothing happens. Show I spray some "Liquid Wrench" type stuff in the to try to loosen things up?

What is the best way to match the paint to fix scratches?

Feel free to answer any or all. Thanks in advance.

Re: engine won't idle unless moving forward

Ron Brown /

First, congratulations!

On the dragging clutch, you most likely need to dis-assemble it to clean out the rust and lube it, if it is dragging. This may require special tools, hopefully, someone with experience will help. You may be able to improve it by washing it out with brake clean while reving the engine a little with the brake applied. If you do this, you must grease the clutch bearing afterwards, it should have a nipple in the center.

On the back brake, the same thing applies, dissasemble it and clean it, sand the drum if it is rusty and lightly grease the pivots and pins, keeping the grease away from the shoes and drum. This gives you a chance to clean and pack the wheel bearing which it probably needs after 37 years.

I can't quite picture what the gas tap looks like but it is never the threads that seal, it is packing of some kind like in an old fashiond faucet. If you can dis-assemble the tap, you can probably make new packing. If not, you will have to replace the tap.

You are on your own on the pain, although most shops specializing in paint for autos can match almost any color for a price.

Good luck,


Re: engine won't idle unless moving forward

gimmejimmie /

That's great that classic is running, I seen last months pic post, nice machine.The Moped Army Forum seems to have the help available for damn near any problem,

Heres my two cents, spend it the way you want.

The high speed vibration could be:

flat spot on old tires... (unless new)

flat spot on chain........(unless new)

bent wheel

bent forks

engine stalls:

my bike won't start either, unless it's moving

adjust your idle screw (when it's warmed up)

clutch engagement too tight

fuel valve leak

teflon tape

new gaskets


rear brakes

don't oil

disc brakes in 63?

put on center stand and work lever/pedal while running, see earlier posts about soft brakes.

not holding your mouth right

listen to what these guys say,

in no particular order:



Ron Brown

Jim C.

Re: engine won't idle unless moving forward

I'm curious..when you try and idle when not moving..are you holding down the brakes to stop the bike? My peugeot had a problem that whenever you depressed the brakes when the bike was idling it'd kill the engine..something to do with the way the bike is wired (i still cant quite figure it out completely..). With mine I had an unreliable spark to begin with because of a bad condensor. As for brakes, to get mine to work good i ended up taking off the wheel and just taking them apart (good opportunity there for chrome-polishing the wheels also). check the shoes to see that they're not too badly worn and get rid of any dirt or gunk thats built up on the shoes and the drum.

Re: engine won't idle unless moving forward

Hey Dude, sounds like you have some weak or broken springs in the clutch, or have stuck in the out position....wish I could be of more help..Doug D

Re: engine won't idle unless moving forward

have you checked the needle valve? turn 2qt then if does not work, try setting it at

1qt hope this helps -tom

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