1976 motobecane 50v electrical problem

after months of perfect running (besides maybe a little inconsistent idling) my moped decided to backfire and stop reving up. when i killed the engine, I was not able to start it up again. I have changed the spark plug, with no different results. I'm not sure what the part is called that houses the electrical components, but whatever that is (by the pedals on the right side of the bike) I cannot get that open. Any comments on what the hell might be wrong w/ this bike? or how to get that piece open?

I'd really appreciate any suggestions.


St. Louis

Re: 1976 motobecane 50v electrical problem

Mike Scouty McScoutington /

to open the magneto you need a piston stop to stop the stroke of the engine. a regular 3/8 drive ratchet will fit in the nut on there. the nut is reverse threaded so you have to tighten it to loosen it. before you go crazyin the electrical system, do you have spark? have you checked it by pulling the spark plug, touching the engine with it and cranking the bike? i would check ground connedtions before jumping into the electrical stuff. you should have a braided wire that runs from your high coil to your engine mounts. also check the grounds at the zenor diode (the heat sink under the headlight). if your zenor went bad you could have blown the condensor. the zenor diode is the voltage regulator for your bike and without it on a 6 volt system (anything pre '78) you will fry condensors all day long. also you want to disconnect your kill switch. you can do this by disconnecting the jumper wire that is on the wire that goes to your high coil. you can just use decompression to kill the bike. your horn will still work if you disconnect this wire so that will still be their.

Re: 1976 motobecane 50v electrical problem

Thanks mike, I have tried to get a spark that way but w/ negative results. How do I go about checking the grounds at the zenor or condensor?

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