top end

[braapbraap]

i just bought a 2000 yz 125 and it seems to run great. the only problem is no work has been done to the motor in 3 yaers. i have heard that you are supposed to change the piston and rings around every year. i am planning on changing the piston, rings, an gaskets and was wondering if i needed to do any work to the cyclinder even if it is not damaged. Im gessing the guy who sold me the bike took excelent care of it to run this good for that long.
thanks for the help.

 

[Xtremesports445]

first off, i'm sure the bike wasn't raced, in which case a 125's top end can last for much longer than what most people think. My guess is that unless you are going to be riding it hard or racing, you could leave the top end as is and it would be fine. and why do work to the cylinder if it's not damaged? unless you want to bore it out or something.

 

[IndyMX]

It might not be a bad idea to tear it down and measure things.

If everything is within tolerance, put it back together and ride!

If there are parts that are worn beyond the manufacturers tolerance, fix it.

 

[braapbraap]

thanks alot