Roketta Top end Rebuild Question By damin69 (Read 593 times)

[damin69]

I have the MC-62-250. Now I have done everything to try and get get this scooter to run at hiway speeds. It just has no zip at all. While checking compression it is only about 125 psi. So after doing some reading and such with the 257cc I had seen that should be a quite a bit higher. As many issues as I had when I first got this scooter with keeping the air cleaner tub to stay on I am thinking that the previous owner had the same issue and basically ended up running sand through the engine and pretty much killing the engine. So enough of the rambling.

I need a bit of help locating some documentation for this motors Torque specs. I have the top end rebuild kit ordered from Scrappy should be here in a week. Then it will be a matter of trying to get some time to pull apart the scooter and GIT R DONE.. sorry watching Larry the cable guy right now.

Thanks in advance.

Todd

[JR]

Todd you better hold off on Scrappy's top end for the linhai! This engine has been known to have 3 different piston sizes and there are those including a member here that will tell you that Scrappy sent them the wrong size piston and rings!

The engine could have 68, 69 or 70mm rings!

JR

[JR]

BTW go to the Yamaha manuals and look at the YY250 service manual, torque values are there.

JR

[damin69]

Jan 11, 2012 21:52:19 GMT -6 JR said:

Todd you better hold off on Scrappy's top end for the linhai! This engine has been known to have 3 different piston sizes and there are those including a member here that will tell you that Scrappy sent them the wrong size piston and rings!

The engine could have 68, 69 or 70mm rings!

JR

Oh man dont tell me that. Crap. That is why I asked in that other thread where to get the BB top end or a good top end.... NUTS.... .

[JR]

Call and hold them up if you can, take her apart and measure it and go from there.

JR

[damin69]

Jan 11, 2012 21:52:19 GMT -6 JR said:

Todd you better hold off on Scrappy's top end for the linhai! This engine has been known to have 3 different piston sizes and there are those including a member here that will tell you that Scrappy sent them the wrong size piston and rings!

The engine could have 68, 69 or 70mm rings!

JR

JR,

If the piston, Sleeve and Rings are all coming in a kit what difference does it make? All coming together in a kit would it not be just like doing a BB upgrade without a bigger piston?