Motobecane engine swap?

I currently have a Motoebcane Mobylette. I know it sits within the 50 series but i have no idea which. The bike is a 1 speed automatic, tops out before 25MPH. Has a Dellorto carb, and prior owner did restore the bike with its original parts.

I am hoping to hit 30-35 MPH, is this possible by swapping out the engine with a new AV7 ebay engine?


Re: Motobecane engine swap?

Dirty30 Dillon /

With some light porting and adjustments, your current motor can achieve those speeds. There's no reason to replace the entire european-built, vintage motor with a modern clone whose quality will not be as good.

Re: Motobecane engine swap?

picts of motor and moped for id purposes,they will assist in opinions here as well.

Re: Motobecane engine swap?

dominic motes /

Then what porting or adjustments shall I make? I honestly have been trying to read old threads but I have never cracked an engine. Nor have I ever rejetted a car or know what to even rejet to or how...

I have even thought about getting a 70cc kit and having a mechanic install it as I dont have the tools to re-port the exhaust or intake nor have the know how.

Re: Motobecane engine swap?

kevin Smellaflange /

watch.... dave fixes his shit... on YouTube

you get not do all the mistakes he makes, but does correct most of them well...don't use a dremel on your ports though, a tiny rifle file set will be good enough.

do the work your self, get a small torque wrench for

variator on the left side, right to tight 80 ft lbs, head bolts13 ft lbs, 11 ft lbs carter bolts criss cross pattern; slow build up to these specs though.

you'll like your moby better that u did it.

Re: Motobecane engine swap?

Search "Poor mans fast moby" for ideas.

Re: Motobecane engine swap?

buy the used 50v stuff off jack on buy sell.

Re: Motobecane engine swap?

Use good old school parts as mentioned above, very little is made as well. Also, go to wiki, read everything Motobecane, especially anything by Rebel Moby, he knows more about these bikes than almost anyone, and was kind enough to write it down for us. (edited)

Re: Motobecane engine swap?

kevin Smellaflange /

that's true but he uses a top dead center tool, but

dave fixes his shit uses sort of a large shoe string

( not the best idea ) but it's a country way to do that iv'e never seen before because i have always had a tdc tool, dave is a country boy where as rebel moby is a guru of rare quality and his volume is down a bit in his vids...they both should be studied.

others are foolishly posting vids with little knowledge. like boat anchor moby or ?

Re: Motobecane engine swap?

Well hot damn! Country boy David here. I’m breaking my long standing tradition of lurking to say that you should not (repeat— should NOT) do a lot of the things I do on my vids. Most of the time, I’m flying by the seat of my pants. Rebel Moby, however, is a god of French Mopeds among us mere mortals. If he says something or does something, take it as gospel. Thanks for the shout out Brent!

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