x9 250/500 engines

[csr305]

Hi,although i have had quite a few x9,s over the years there is one thing that intrigues me that i dont know the answer to.Im hopeful that someone will have the answer to my question ,which is, Does the top end ie barrel piston and head from a 500 x9 fit to the 250 evo motor,thus allowing an easy upgrade. I say upgrade cautiously,as i know that many 250 owners would dispute that,so forgive me for this.Iam longing to know the answer if anyone knows,otherwise im really enjoying my first 250 x9.thanks and stay safe,  john

[unchained]

I doubt it John, the 2 engines are vastly different.

Bob

[Dave Milnes]

The crankcase of the 250 and 500 are quite different and the pitch of the barrel/head studs probably different. The gasket sets for the two motors are unique so I would doubt it could be made to work without some serious machining.
The stroke may also be where the 500 makes it's 460cc's from rather than just the bore and the manifold for the 500 has the injector so you may have to make up a manifold to adapt the carb from the 250.
I bet the barrel and head from the 300/350 could be fitted, or even the complete motor and that may well accept the manifold and carb from the 250.

[csr305]

thanks dave and others for replies,much appreciated and i note what you say,best regards,  john