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Head identification.

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I bought my wife an 04 crf250x and guy I purchased it from said previous owner put an 250r head on it. What would be the purpose of this? And how would I know which year head is on. I see KRN stamped on head, JO49 and

FI 49 engraved on head.

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Generally replacing or upgrading the 04 cyl head is a good idea and often times needed due to many hours. Depending on the hours the original head may have been worn out or needed valve work. 

If you dont know what head is on it and want to find out here is a link that helps to identify which R head it is by port shape or design,  just scroll down the page about halfway.


Unfortunately you cant see the ports without doing some work to get visual access.

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KRN is the CRF250R product code

KSC is the CRF250X product code


However, early CRF250X models used CRF250R heads.  You have to actually compare heads from known models to yours in order to know for sure. Or, look at some pictures of known heads and compare to yours.  Different 250R and 250X heads perform differently and some riders like to choose according to these differences.  For example, low-end torquer vs top-end screamer.

Check it out:



Ouch, 205'd.  I'm a slow typer.


Edited by ramz

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