Motobecane help

My motobecane moped bogs almost right out after I get it to full throttle. I've got a carb that's been cleaned and rebuilt, tuned and works on all my other mobys. New plug, and gaskets all around. Please help

Re: Motobecane help

Pushrod Fifty /

Read all that Rebelmoby wrote about them. The first one I had showed a leak at the decomp when I did a leakdown test. I lapped the valve with grinding compound and that fixed it.

Re: Motobecane help

YEP - do a leak down always on any fresh rebuild because even brand new everything can leak .

ALSO check your timing: points make sure you gap them at index then set the timing to 1,5mm BTDC, for CDI you can set them at 1,2mm BTDC.

Which carb? Is it one transplanted from another bike?

If it is a Gurtner then perhaps the float height needs to be properly set.

Jet and emulsion tube might need cleaning.

You have multiple posts for Mobys - which bike? (You say mid-late 1960s) Maybe a picture?

Re: Motobecane help

Tri-ped Dave O.D.B. /

and just because the carb "works" in all the other Mobys. is it jetted to this one?

Re: Motobecane help

Pushrod Fifty /

Gas may be only trickling from the tank if there is a restriction, check by pulling the line off of the carb and letting it run into a container. Check that your variator is working correctly, its naturally in high gear mode until the engine revs, then downshifts, then upshifts as you accelerate. If its stuck then your taking off in high gear. Or maybe upshifting too fast. (edited)

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