putting a xj750 heads on a xj700 can i do it

iam looking to c if i can put a bigger head on my xj700,is it possible and if so what do i need to do,can i just put the xj750 piston and rings on the piston rod and the head from the 750,will it work

 

I've had/have both bikes....trying to think of any glaring differences...can't right now. Not sure why you would want to do it though...If I'm not mistaken, the xj700 would take the 750 in a race. 50 cc's is not that much...take a compression reading, and if low, pull the head and jugs...then hone the jugs, lap the valves, new gaskets and go from there. It's EZ on an air head.

 

Care to race?

 

Are we talking aircooled or watercooled?

If you're talking 750X heads on a 700X, that was covered in this thread. General consensus is that the two heads are identical -- the difference lies not in the bore, but the stroke.

As for aircooled, as Yamaha didn't have an american 750 model that year, and hence one would need heads from an earlier model year, I'm not all that certain that the idea would work. Someone please correct me if I'm wrong.

 

schmuckaholic how do you know what year he has?

 

I assume he's talking about the earlier xj750, but who knows.....maybe he isn't in the US and DOES have the later '750!

I don't know as I'd want to put the older head on, seems like going backward to me. my opinion.

It'll be interesting to see where this one goes................

dave fox

 

He never did specify, but since he wants to transplant the heads onto a 700, that implies that the bike in question is an 85 or an 86. AFAIK, those were the only two years that a 700cc engine was produced for the XJ family.

Possible, but... was there a 750 aircooled? I'm seeing no reference to it.

 

suuure...I have 2 700's....which one? the one with the Radiator or the one without???