What should the compression be on a 1989 KDX200?

just bought a 1989 kdx200 and the compression is between 167-170 ish. is that good for that motor? what is it usually with a new top end? and what is the lowest those motors will run with? thanks

That's good. 155-185 is the good range. They will run supposedly down to 120. That is the stated useable low reading.

ok thanks dirt duchess! the guy i bought it off of says its never been rebuilt ever so i guess it hasn't been used much

Mine was showing 168 after my last rebuild with a re-plated cylinder. Usable range according to my 89 service manual is 119 - 185psi.

thanks juliend its good to know the range its use able in. i think mine will be good for years with 170

my bike had nothing commemoration wise and it still ran ok (once you got it going), after it was rebuilt it had 162psi

Well I don't know how mine has 170 than and I've tested it with 2 diffrent guages and its the same lol I guess its just got good compression from the factory.

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