Compression on 93 cr250

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Oct 30, 2002
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#1
I'm planning on doing a compression test on my 93cr250 later this week. I have the service manual but can't find any info on what the acceptable compression range is.

If anybody knows what the compression should be please let me know (I'm guessing 140-160).

Thanks
 

RM_guy

Moderator /
Damn Yankees
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Nov 21, 2000
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#2
The compression should be 185 to 200 psi but that is only an indication as to the health of the top end. The only way to really know if anything needs to be replaced is to tear it down and measure things.

Usually if the compression drops by 10%, you are passed the wear limits but again, it's only an indication and only measuring the parts will let you know for sure. I like to measure the compression after doing a complete top end as a base line and then check it after 20 hours or so depending on how hard I'm riding.

I'd suggest getting a manual if you plan on doing your own maintenance.
 
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#3
Wow, 185 to 200 is a lot higher than I expected. I have the honda manual but for some reason it doesn't have the spec in there.

I have a new top-end with piston for the bike (I just bought the bike from a buddy a week ago) and was trying to decide if I should do it now or wait another month.

The bike rides pretty well but I had the cr and my 90kdx200 out last weekend and the kdx was pulling as hard as the cr (maybe harder). That's why I'm checking the compression - I figured it was a good place to start looking for missing performance.

Any ideas are welcome...also, if anyone knows of a good site for info on the cr250 of that vintage please let me know.

I'm looking forward to really going over it soon and I like to know what other people have found with cr's of this era.