Motobecane won't Idle

I recently found a Motobecane 50v in the trash. My guess is it's either a 79 or an 80. Just got it running really well. Starts no problem, accellerates fine, reaches its top speed, however it does not idle. I thought this was because it was missing the idle screw, but i just bought an idle screw for a motobecane and it's still not idling. The Carb is spotless, I cleaned it today still won't idle. Now it is missing the back half of the exhaust. The exhaust also wobbles around, but i did tighten it up. It still wobbles. Could this be my problem? It sounds crazy to me. This is my first motobecane, i'm not familiar with their common problems. Any help would be great.


Re: Motobecane won't Idle

Will it idle on the kick stand, but stops when you pull the brakes.

If so, you probably need to clean your clutch pads.

Or does it never idle

If so the idle circuit in the carb may be clogged. the idle circuit goes through the higher hole in the carb, up through the throttle cap, down a different pipe, around the outer edge of the diffuser, and up through 2 small holes in the venturi.

Get your self an endcap for the muffler or you could overheat, and go deaf

Re: Motobecane won't Idle

The Gurtner carb has many pasage ways which need to be clean.

I spent about 2+ hours cleaning mine and everytime I thought I was done more stuff came out.

Use an air compressor and a can of carb cleaner or throttle plate cleaner.

It's not over flowing with fuel is it?


Re: Motobecane won't Idle

I pulled it again right after i made the post and noticed all of these passage ways. They were all fine, but i cleaned them just to be sure. I noticed the notch on the throttle slide was bent i bent it back, but as i was putting it back in the carbureator, it just snapped off, now it won't run. It isn't oferflowing. Everything looks fine in the carb, i don't know what to do about this idle thing.

Re: Motobecane won't Idle

Sounds like it's new carb time, if it just broke.

By the way nice score!

Out of the trash I mean.

A lack of proper idle can indicate bad crank seals or a vacuume leak.


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