From AV7 to AV10

Here’s a motobecane 50cc engine I built for a customer who wants to swap his av7 engine 2 ports cylinder inducted and experience the power of a better av10 engine 3 ports case inducted reed valve with lubricating holes for the crank bearings.

I’m using used stock av10 cases, used crank + new bearings and seals, new 50cc doppler kit, used stock RMZ head with decomp, used stock cdi (also have a back up new mvt cdi), new 19 carb, new doppler exhaust, new doppler er3 variator with bearing clutch function, stock double spring, no launch lever.

I’m using my wonder bread moby frame to test the engine, once perfectly tuned I’ll send it back to Chicago, ready to mount and blast after re-jetting.

If you’re interested in a similar set-up for your moby or build a whole bike just contact Tomahawk.

Short video 1st start a mano:

2h break in session with rich carburetion + heavy variator weights, and old doppler pipe (thx Tracy!)

The engine is ready for final test runs, carb and variator tuning. Then pack it and ship it.

Motobecane stock cases available at

AV7                                                                     AV10


Bonus pics:

Back from my meeting with Santa Claus after reinstalling my 50cc Bidalot engine, blasting everybody’s ears and racing some Ford Mustangs on Hollywood Blvd with my screaming 12,000 rpms pressing hard on the launch lever. I never get tired of it!

The perfect plug, the color looks richer in real with a nice light chocolate brown/brick red.


  1. tomahawktuning

    Yay. I was happily surprised.

    First spark and boom! I must have “the touch” now.

    Since the engine has a bearing clutch variator it’s hard to push start it but no need for a kick start or the cardboard trick on that one, just use your hand or foot! 😉

    • tomahawktuning

      I didn’t make that adapter plate, it came with it. It would take time to make one and expensive in labor. I don’t have any left.

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