compression ? cr250

[klu954]

This is my first post on the board but have been reading for awhile! My ? is I just bought a 2001 cr 250 and the guy said it had head work done to it and we checked the compression and it was 216lbs. this normal? :cool:

 

[sick 96 250]

sounds normal, both my 250's were 208 and 218 psi

 

[klu954]

were both your bikes stock or not?

 

[Studboy]

If you pull the head off, you will be able to tell if the head has been cut or not.

 

[sick 96 250]

no engine work, so the cylinder was stock, both have weisco pistons but not the high compression ones so yeah the heads are both stock

 

[klu954]

ok thanks I was thinking of taking it apart to see if it needed to be replaced anyway! Any of you ever heard of supercharging ? A guy from my local shop said you drill a hole in the piston at the exhaust port or something? any comments? :bang:

 

[Studboy]

Supercharging by drilling a hole in the exhaust side of the piston. I think that the guy at your local shop is on crack!!! The only reason that you would drill a hole there is to provide lube to the exhaust bridge (if there even is one on that bike).

 

[klu954]

Well I didn't know anything about it either but I'm new to the 2 stroke world! :aj:

 

[darringer]

My 99cr250 pulls 215-220psi consistently, even with a well-worn top end. It is all stock except for the wiseco piston. That sounds like it is right where it should be. "Head work" can mean almost anything.

 

[klu954]

I talked to the previous owner today and he said the head was supposed to have been cut 10 thous. if so my compession should be alot more shouldnt it?

 

[Pete Payne]

.010" ( ten thous ) would only give ya an extra 10 lbs of comp. if took off of the gasket surface.