What compression should my 2000 KX250 have?

[Tardboy]

What compression should my 2000 KX250 have?
I put a gauge on it and it only reads 120 psi.
Is this ok?

[Sandblaster]

For 92-00 KX250 it should be 780-1220 kPa or 114-176 PSI
So your a bit on the low side.
Didn't you just put a new top end on it?

[Tardboy]

It's been about 2 seasons worth of ridin.
Looks like I got to do a top end and I'm broke

[Sandblaster]

Just thinking out loud here, when you did your compression test did you hold the throttle all the way open?

[Tardboy]

Wait, hold the throttle wide open?
No, I didn't open it at all.
Would this make it read low?

[Sandblaster]

If you didn't hold the throttle open then the engine could not suck in enough air.
So try it again and see what readings you get.
My bet is you will gain 20-30 psi.

[Tardboy]

Ok, I'll get the tester tomorrow and try it again.
Thank you!!!!!!!!!!!

[Sandblaster]

No problem, hopefully this will help.
Curious as to why you ran the compression test to begin with?

[Tardboy]

Oh, ah it was because it seemed to loose a little power an when it idles it runs too fast so I adjust the idle and then it runs fine for a bit and then it is too low.
You think I need to jet it?

[Sandblaster]

Honestly, it sounds like a air leak or your jetting is too lean.
But if I had to guess I would say air leak.
Did the bike run fine with the current jetting before you started having surging?
How does your boot look?