hi there i have just purchased a 2005 ktm sx 125, and i am just wondering how to do compression checks as im not to sure and dont want to blow the top end...thanx alot:D
I didn't really know how to either but you should buy a tester and screw it in where your sparkplug goes and kick it and the gauge should tell you what it is. you'll have to look in your manual to find out what it's supposed to be.
If your wanting to inspect the motor just a compression check won't tell you much. If you don't want to take the top end apart, a leak down would be a good tool as well.
A leak down is nice to say but 99.9% of the guys don't know how to do one and even if they thought they did they wouldn't have the equipment. A leak down check is used to check the case gaskets and left and right side crank seals.
The most common and easiest compression check is a static check. This is done by screwing in the proper hose with adapter into the spark plug hole. Once that's done hold the kill switch, twist the throttle wide open and kick until the pressure stops rising. 180+ psi would be a good number to see, less than that would be an indication of worn rings, piston and rings, bore or valve seats.
Be sure to do the compression check on a warm engine so the parts will be expanded to their normal size.
OK, just went back and read your post. Skip the valve seat comment, the rest holds true.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
