CR250 to 390 Swap?

Will a 390 top end fit my 2065 CR250 bottom end?

Thanks.

What are you trying to do here, turn your 250 into a 390? or do you just want to know if the 390 cylinder will bolt up to the cases? What year 390 top end ? The 390 has a longer stroke than the 250 so if your looking to build a 390 you may as well start with one to begin with as a core engine might be cheaper to buy than a rod kit. I was going to build a 250cc engine to stick in my 77 390CR that way I could race one bike in two different classes with a quick engine change but never could find any 2959 engine cases so I gave up on that idea.

I have a 2065 Bottom end I was planning on rebuilding. So I am buying a rod kit anyway. I don't have a 390 top end so I would have to find one that would fit.

I'm intrigued by the idea.

Ok so your going to build one. I have a 77 390 cylinder sitting on the bench I can see if if the bolt spacing is the same and check it to a 2042 engine.

the bolt spacing is the same.
however,, the head, rod, bearings, pipe, ect, are all different...
it might be easier to just buy a used 390 engine... and find a good used pipe as well.

While were on 390 topic... anybody have a 77 390 motor??

Sorry to hijack the thread!

Yes I have one, is their something you want to know about it?

(NO it's not for sale)

You are killing me Tommie d... nothing like making a grown man cry!

ill be selling all my 390 stuff... have other Husky interests..and need to finsih clearing the stable.
it will be a all or nothing deal.. 79 and 80 vintage