80 750 to 1100 conversion questions

[Guest]

Hello all, I am going to look at a very nice 80 gs750e next week, only issue is, according to the seller, the engine is siezed. I have no problem with that as I have a solid 750e sitting in my garage that I wil just transplant the bodywork onto for now. So, the questions are: does anyone make a 7 to 11 conversion "kit"? What all will I need? I am assuming some things here, mainly that I will need a set of 1100 jugs, pistons, complete head and cams, new cam chain, gaskets etc. Are there differences in head size/shape that will change frame clearance? Are there any threads here that show what/how to do this? I did a couple searches but came up dry. Any help would be appreciated.

[7981GS]

To start with, you would need a complete 1100 engine.

Eric

[Cdnpt1]

For some reason I thought the only difference between the 750 in the 1100 in those years was the bore. I figure a complete engine would be the cheaper way to go anyway

[Jedz123]

nope. A complete Motor swap will be needed if you want liter. Think biggest you can get out of a 750 is 850, maybe 900... Someone chime in on that.

[mrbill5491]

Not sure I would want a 1100 on a 750 bottom end. the 750 is friction bearing and the 1100 is roller bearing (80-81s).

[Cdnpt1]

Not so much worried about that, sounds like it isn't an issue anyway. When the time comes I will go looking for an 1100 motor to transplant.

[madbikebreaker]

So what I'm hearing is the similar year 1100 motor is a bolt in? Sounds almost to good to be true.

[Cdnpt1]

They should be, from what I understand after some more research, the motors have only internal differences so it should be a straight across swap. If I am wrong(which isn't unusual) someone will be along to point us in the right direction.

[hampshirehog]

You'll need 1100 carbs if you want the thing to play as an 1100. They'll need the front part of an 1100 airbox. And the forks are a bit spindly for all that extra oomph you'll get. And the swinging arm is a bit weak - nearly the same as the 8 valve 1000 so not a killer deal but still less than I would want.

[Cdnpt1]

I just read that the only issue with the 1100 in the 750 frame is the bottom mounting bracket under the crank doesn't line up so a new bracket needs to be fabbed.

[gearhead13]

I just read that the only issue with the 1100 in the 750 frame is the bottom mounting bracket under the crank doesn't line up so a new bracket needs to be fabbed.

Yup, thats the only mount that doesn't line up. Some guys run without it. When I did my swap I already had pods, so no airbox issues, and my V&H header fit fine. The electrical connections are mostly the same.
The 1100 has a much longer stroke and the bore is only 5mm bigger than the 750. That makes the 1100 a super torque monster compared to the 750.
I also swapped the front end and rear swinger over to help cope with the extra torque.