Gy6 By dirtyharry10 (Read 588 times)

[dirtyharry10]

My engine is stamped with 1p39qmb instead of the the standard 139qmb, i have heard different theories about the p anybody know for sure and will parts for the 139qmb fit my tao tao 50, first time poster thanks in advance. 

[Alleyoop]

Only way to really find out is to take the head off and measure the piston, if your lucky it is a 63cc motor which will also have bigger valves as well.

Some 1P39QMB motors are the same as the 139QMB stamped motors so the only way to really find out is to take the head off. The other way you can tell right off the bat is STOCK they will do a REAL 35+MPH while the regular 139QMB will not.
Alleyoop

[jct842]

I wonder if there isn"t some marking on the heads to show the differences. If the only difference is underneath with the larger valves how do the importers order parts? Most items have part numbers. The 139 numbers being on the engine case would have little to do with what piston and cyl that is installed for sure. Maybe some one in parts sales could chime in.

[katastruff]

1= One cylinder

P= Horizontal type

39= Bore size

Q= Forced air cooling

M= Engine use (M for motorcycle)

B = Displacment (B stands for 50cc)

Source:Tech Talk with Mo!

That being said, im with Alleyoop on how to find out if your's is one of them secret and rare bigger 139qmb.

[jct842]

Except the chinese do not always stick to the rules, and can install what ever top end they have handy.

[JR]