engine swap

[lollydude]

I have a xj 750 rk and a xj1100 engine. Does anyone know if the xj1100 engine will fit in the 750 frame? Will it be too much of a pain or will all the mounting holes line up? What's yalls thoughts on the subject.

[uk1.1s]

shoe-horning

I suppose the first place I'd start was working out if you can physically fit the engine in the gap.

The XS11 engine (as anyone who's removed one will tell you) is a pretty tight fit in the 11 frame as it is. You would have to be sure it would fit - measure maximum distance between the bottom frame rail and top of the frame (particularly at the front).

Length again is an issue as the 11 is a looonngg engine, particularly with the middle gear box.

Once in you will have to mount the engine. You must have seen the '60's cafe racers made out of Brit bikes. The most effective being the Triton - Triumph Bonnie engine in a Norton Featherbed frame. Well - what you are after doing is similar and involves making up one-off engine plates to fit - as I'll guarantee that you won't be able to line up all those mounting holes. The downside is that Triton building has been a small industry since the mid-60's and you can buy the plates over the counter .... whereas you'll be on your own measuring all the distances and mounting positions for the brackets to work. Some friends have used aircraft grade aluminium plate for this - bit thicker than the original steel - but polishes up nicely.

Obviously there will be knock-on effects of "will the carbs fit", "I'll have to make an airbox as nothing I have is that shape" and the famous - "now there's nowhere for the battery" All part of the one-off builders fun ...so I hear!

The drive could pose a problem - shaft alignment / wheel alignment - especially if you have to mount the engine slightly off centre to help fit it. You may have to cut and weld the shaft also to shorten it in the 750 frame.

Just a few thoughts - I have a few mates in the custom scene who really enjoy this sort of thing, although they often go down the route of a custom frame too.

Good luck with the project