What compression should my 2000 KX250 have?

Mechanical problems discussed for Dirt Bikes and Dual Sport Bikes
Tardboy

What compression should my 2000 KX250 have?

Post by Tardboy » Wed Jan 30, 2013 10:32 pm

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

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Sandblaster
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Re: What compression should my 2000 KX250 have?

Post by Sandblaster » Thu Jan 31, 2013 2:39 am

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?
If bikes are for kids I'll never grow up.

Tardboy

Re: What compression should my 2000 KX250 have?

Post by Tardboy » Thu Jan 31, 2013 2:49 am

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

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Re: What compression should my 2000 KX250 have?

Post by Sandblaster » Thu Jan 31, 2013 2:51 am

Just thinking out loud here, when you did your compression test did you hold the throttle all the way open?
If bikes are for kids I'll never grow up.

Tardboy

Re: What compression should my 2000 KX250 have?

Post by Tardboy » Thu Jan 31, 2013 2:53 am

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

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Re: What compression should my 2000 KX250 have?

Post by Sandblaster » Thu Jan 31, 2013 2:56 am

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.
If bikes are for kids I'll never grow up.

Tardboy

Re: What compression should my 2000 KX250 have?

Post by Tardboy » Thu Jan 31, 2013 2:57 am

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

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Re: What compression should my 2000 KX250 have?

Post by Sandblaster » Thu Jan 31, 2013 3:02 am

No problem, hopefully this will help.
Curious as to why you ran the compression test to begin with?
If bikes are for kids I'll never grow up.

Tardboy

Re: What compression should my 2000 KX250 have?

Post by Tardboy » Thu Jan 31, 2013 3:07 am

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?

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Re: What compression should my 2000 KX250 have?

Post by Sandblaster » Thu Jan 31, 2013 4:39 am

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?
If bikes are for kids I'll never grow up.

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