Motobecane Carb just shot??

I have tried everything to get my Motobecane to run and idle properly, but nothing has worked. There is simply too much gas getting through the carb. My sparg plugs keep getting covered with a dry, black soot. I have tried smaller jets, adjusting the choke, adjusting air screw, etc., etc, etc. I have spent probably 15 hours trying to get this moped to run the way it should, but nothing has worked.

Could my carb just be shot? Do they just wear out internally?

Larry

Re: Motobecane Carb just shot??

Matt Lorence /

Im having a similar problem, check to see if the needle on your float is straight, mine wasnt very bent, and the only way I could tell was to put it in the drill press and check for wobble. I straightened it a little, and i got my 50V to run. I imagine if I could straighten it all the way, it would run alot better.

Re: Motobecane Carb just shot??

moped mike /

clean out the air filter, If the air filter is pluged with dirt or if it has a real big hole in it, that would cause the card to get to much gas,, and have you checked the flout in the carb, maybe it has a hole in it or is shot to hell,,

Re: Motobecane Carb just shot??

I've tried 4 different floats and the result is always the same. I don't know what else to do other than to replace the carb.

Re: Motobecane Carb just shot??

Matt Lorence /

Hmmm. Well, I pulled everything out of the carb that I could, every screw, the peices for the jet, anything you can get out. Cleaned everything with carb cleaner, and ran a piece of wire thru all openings to clean them up. Make sure the jet goes back in correctly, so it seats and seals right. If that doesnt work, you should sell the carb to me for real cheap : )

Re: Motobecane Carb just shot??

Matt,

Maybe I'll give it one more shot. I'll go through it one more time and see what happens. Maybe three times is a charm?

Thanks,

Larry

Re: Motobecane Carb just shot??

Hi Larry.

Check the air and fuel passages. There should be an idle air intake on the inlet side of the carb that connects up with the main needle jet. They are small diameter and can clog up. This could make the engine run rich at idle. A can of compressed air and a small diameter spray tube help. Sometimes is impossible to see the inner part of the passages. Carb cleaner should be able to flow through the passages. If it doesn't, then a passage is clogged.

I had an old Encarwi-Bing that I had cleaned ultrasonically in carb cleaner. The carb wasn't giving any fuel. When I looked carefully, there was a membrane over the opening of the main jet (this carb didn't use a needle in the main jet). Some insect must have put a cocoon on it. I could see light shining through the jet, but didn't see the almost transparent cocoon until I looked carefully. I removed it with a soft plastic wire, and the carb worked fine afterwards.

Paul

Re: Motobecane Carb just shot??

have you tried disconnecting your exhaust and then starting your engine. maybe your exhaust is clogged. it may beworth a quick check.

Re: Motobecane Carb just shot??

have you tried disconnecting your exhaust and then starting your engine. maybe your exhaust is clogged. it may be worth a quick check.

Re: Motobecane Carb just shot??

Been there done that. I cleaned the baffle and exhaust port before I rebuilt the motor. They are both free and clear of carbon. The problem is clearly too much fuel to the engine. I've already gone down two jets sizes and that has made little difference. Today I'm re-soaking the carb in carb cleaner, I just straightened out the float as near perfect as I could, and I'm gonna blow compressed air through the passageways and jets after soaking it overnight. Let's see what happens....

Thanks for all the help everyone!

Larry

Re: Motobecane Carb just shot??

I have the same problem with my 79 Mbecane, and i too have had no success. My carb is perfectly clean and I'm beginning to think it could be the end of it. I've heard that gurtner carb's are terrible and mostly problematic, especially on motobecanes. Keep us posted on what works.

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