[Jonnyboi69]

hi there I'm new to this site and im wondering if you can help, me please, I recently bought a 2004 crf250x (non-runner) which I was made to believe it just needed a piston

I took it to my local motorcycle engineer to be fixed and to our horror found that the full cylinder head, barrel, and piston needed changing or at least a major refurbishment to the head, cam and barrel, after weeks of searching I found a newly refurbished crf250r topend complete with new valves all shimmed up ready to fit the bike. I've been made to believe that the stock cam and exhaust on a 250x is governed to meet highway regulations, but the thing is now I've got the 250r cam and de-restricted the back box but the air box on the x is also restricted so it means changing the sub-frame and air box to an r, which is just more money and time so ive cut open the top of the air box as shown in the ccc mods (not quite as open as the r) see the problem now is there seems to be a problem with the fuel/air intake there's something not quite right,

What jetting would you recommend for me I'm roughly 1500ft above sea level and the temps are around 5 degree Celsius ?? Thank you in advance

[michelinx9]

The above statement, this is a great value for me and many people here.

[crfsonly]

The head is bolt on compatible with the 250X. As is the cam since it on the R. If the cam was going on a X head we'd have to discuss valve springs, buckets and decomp spring.