1978 Motobecane Mobylette... help

I just purchased a 1978 Motobecane Mobylette. There are some troubles... you have to push it to get it to run and going up any hill it stops. It has no power and its top speed is around 15 mph. It only has 1,000 miles on it, all original parts including tires, it seems in fine shape, except for its peformance. Any ideas or people to talk to in the Twin Cities (Minneapolis/St. Paul) area would be appreciated.


Re: 1978 Motobecane Mobylette... help

Once again.Read Fred's essay (posted in this forum,just scroll down and look for it).You can't fail to solve it if you follow this all-encompassing advice.BYE!

Re: 1978 Motobecane Mobylette... help

Thanks I found the manual and printed it out! Hopefully this will help. I'll keep you posted.


Re: 1978 Motobecane Mobylette... help

Hey,Dan! Don't forget to thank Fred! He put a ton of work into that essay so you and I could go step by step,and he keeps posting it every once in a while to help everybody out.BYE!

Re: 1978 Motobecane Mobylette... help

Ray Sanders /

A big "me too!" goes out to you, as I just got mine up and running.

See photo archive, 1978 Motobecane Mobylette 50V :-)

Clean the fuel tank Clean the carb, replace the fuel line, replace the spark plug (Bosch Platinum works nicely.)

Mopedjunkyard.com has a rough exploded view of the carb that helped me get my carb back together after a few issues after cleaning it.

Try putting on the choke, and see if it helps, the choke is basically a bypass fuel jet, and I'll bet the passage from the fuel bowl float to the fuel jet is clogged.

One other thing to take into consideration is that carbugs.com lists a recall on ALL 1975-1980 Motobecane Mobylette Mopeds. I guess the brakes and lights aren't up to federal specs for their top speed (30 M.P.H or more) so some bikes may have some sort of a wedge block ring on the variable transmission to govern the bike down to about 20.

Re: 1978 Motobecane Mobylette... help

Hey dan I a;so live in the twin cities and tring to get my 78 moby to work. It has been sitting for 15 years now since I last used it. Need to take the head off though since the piston is froze. Let's see if we can help each other out with advice and rooting when we get them running then we could cruise university with the hot rods.

Re: 1978 Motobecane Mobylette... help


I have got a 1968 mobylette. If the drive belt os worn, then this could result in a loss of power. If it starts easily with out the belt slipping, then the belt is probaly fine. The timing could need adjusting, you might need to increase it a bit. Or the choke valve might be blocked. My choke stopped working and ever since there has been a loss of power. It could mean that the carbirator might be blocked some where.

Hope this helps,


Re: 1978 Motobecane Mobylette... help

good ideas mark,

but i hate to point out that youre about a year too late. It is good to post although for archive purposes.



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