Technical question: Is gearbox casing same for xs250/360/400?

[Greasey Fingers]

Guys I have a technical question. Im pretty sure it is but thought I better ask here. Is the gearbox casings the same for the xs250/360/400?

What I want to know is can I put the xs360 crank straight in a xs250 gearbox casing? Pretty sure the top end will just go straight on, just want to confirm the gearbox internals.

Also what difference does having the xs360 crank in there make compared to the xs250 crank in regards to engine performance? Is it better to use the proper 360 crank as opposed to just bolting the complete 360 top end onto a 250 bottom end? Or is it worth the extra effort to change out all the 250 gearbox internals for the 360 gearbox internals?

I need to keep my current engine number as it is registered with that number

cheers guys

 

[xschris]

I don't think there is any issue with the crank or lower guts. It is the piston sleeves fitting into the case. The xs250 case is smaller than the 360/400. I think there is a thread on this in the forum.

 

[Greasey Fingers]

Cheers chris, that's something I need to confirm thanks for pointing that out.

Has anyone here bolted a 400 head straight onto a 250 gearbox? Any issues with the sleeves going in?

 

[xschris]

http://xs400.com/forum/showthread.php?t=6555 Here you go. I believe It was the mid 70's xs250 that had the smaller case holes for the jugs.

 

[Greasey Fingers]

Thanks chris mine is a 79 I think it should be ok....I hope!! Ill be sure to confirm this on this thread once I find out 100% then there will be a definite answer on the forum if someone else needs to know.

 

[arfstrom]

When I blew my kick start journal, I was able to order a case from eBay, and then just the bottom needed to be replaced, which is what I did, and I was able to retain all the parts that have the same series number.