Zuma 50cc 4T Crankshaft  By  mopojo (Read 1,035 times)

What engine type? Look on the engine somewhere it should say. Is it 139QMB? It looks like my crank, here is a link to one on ebay from a seller I buy a lot of parts from. Very good customer service, really fast shipping usually arrive before expected date, but I can't say that'll be the same for around now when everyones ordering stuff lol. If you message them before buying it you can also tell them about the scoot you are trying to get parts for and they will look up compatibility for you.

www.ebay.com/itm/Scooter-Crankshaft-139QMB-50cc-Scooter-Engine-Rebuild-Chinese-Scooter-Parts-/161009017302

mopojo As far as if the fully splined ones are compatible, I would think not because the rounded area you have is where your variator and discs and belt will rotate on, and if it was splined fully it might cause more friction than there should be I would think and possibly cause overheating, breaking parts, or just a really bad time. But don't take my word for it, I only have a moderate understanding of scooters.

What about on the engine fan cover? Usually I see a small metal plate there with info on the scoot. But yeah ask the seller, and might as well ask on zuma forums too, never can be TOO informed lol.

lain wrote:
"As far as if the fully splined ones are compatible, I would think not because the rounded area you have is where your variator and discs and belt will rotate on, ..."
If the belt actually touches anything close to the crank it is the boss. However, the variator plate closest to case is not fitted for splines (smooth) and fits to the shaft snugly. I don't know if that is an issue.
I will call dude and tell him to check the fan housing. the bike was buried and chained to a concrete wall. lol

@ Alleyoop:
2012 he swears. The first question I asked after researching ebay, amazon and general interwebs was if he was sure it was not a 2 stroke. He rides Harleys and knows it's a 4T.
Guess I will have to ride back out there and dig it out. Gotta tear it apart eventually anyway.
While posting I found a video of exactly what I saw when I pulled the destroyed parts off his bike. Video says it's a Yamaha 2012 C3.
No star "washer" on drive face-plate.
Partially splined.



Warning: Video long and drawn out.

Many would charge 75 bucks just to replace the diaphram. If they don't want to pay they should learn to do it themselves. Just to take the time to look at it is usually between 40 and 75 bucks.