motobecane starting trouble

ok i have gotten a step foward. I went from no spark to spark. My moped still does not run. When i spray starting fluid and try fo start all i get are backfires. About 4 to 5 of them and the it stops. What could the problem be???

The moped is a 1978 motobecane mobylette..

thansk for the help!


Re: motobecane starting trouble

you decompression valve may not be sealing properly, or the timing may be off.

We need some history.

-Has the bike run recently?

-If so how did it run the last time it ran?

If you just bought it, did the seller say it just needed a carb cleaning?

(this is usually a secret code meaning the moped is a total waste)

Re: motobecane starting trouble

Clean the carb, unclog the pipe. My mobylette won't start unless you pedal it like a 10th of a mile, but it starts every time and runs awsome.

Re: motobecane starting trouble

never had it running before. I cleaned the carb but i dont think its a fuel flow problem. When i spray starting fluid in the spark plug hole it will just backfire. The exhaust is clean and i have been peddling for ever!!! the points were just cleaned by me and i gapped them too as suggested by the manual. The spark does not loook like it is always in sync. Is this a timing issue??when i had the magneto apart i could not see how to adjust the timing!!! i checked the poston to make sure it was not holed. Also i checked the decompression valve and it seemed to be sealing. When i pull the decompression lever to start the peddling and when i release it you can deffinately hear a checge in sound. So.... What could the problem be>???? I love the moped it looks like it is new and i hope to have it running soon!!!

Thansk for all the help!!


Re: motobecane starting trouble

read the link in my first post to check timing

What do you mean "The spark does not loook like it is always in sync"

in sync with what? Is it not firing regularly (one spark for every revolution)

Re: motobecane starting trouble

the spark is speratic. like spar spark... spark.............spark

Re: motobecane starting trouble

Sounds like the ignition is marginal. First things to check are the condition & setting of the points, and the condition of the plug wire, plug cap and plug.

Remove the plug wire from the coil, and measure the resistance from the end of the wire to the center contact of the cap. Should be 1-5K ohms. If not, search the forum for posts about plug caps and wires. There is plenty of good info in the archives.

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