05 300 exc compression?

I just bought a 2005 ktm 300 exc and when I tested the compression(cold) the guage read 148psi. What should it be and how low before I have to do the top end?

Try it warmed-up. How does your guage read? I mean, all guages are slightly different, and some read high, and some low. Make sure to hold throttle open. 150 seems a bit low, but not necessarily terrible.

A 300 will run with 120 but not well. Start saving for a top end. If you let it go too long you will need to replate the cylinder.

Thanks for the replies, I have a two day ride planned for memorial day, when I get back I'll work on a new top end.

The problem ois that all guages will read different. It is best to get a base line when you rebuild. That is what I SHOULD have done. Heck, I will hardly ride it for three years, get bored, and rebuild. Good luck. If you want a 250 bore I will trade ya... pluse cash..?

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