1100 16 valve engine into 1981 GS750 frame

[headsbikesmopars]

Thinking about dropping an 1100 16 valve engine into a 1981 GS750 frame. I am sure it will fit because it has a 16 valve 750 engine now. Just concerned about the frame and the torque the 1100 puts out. If anyone has done this , was the frame beefed up or strengthened for the larger (power) engine ? Please advise and thanks.

TB

 

[Guest]

I think the frame may be too narrow. I know they use the same body work, but I think the frames are different. From Parts Outlaw:
'81 GS750E frame # 41100-45400-019
'81 GS1100E frame # 41100-49201-019

 

[Guest]

Lower rear mount is the same. Front mounts need custom plates. Air must move forward an inch or so.

 

[Guest]

This isnt my own knowledge. I borrowed it from the internet. I googled gs 750 1100 and found a thread.

 

[tkent02]

I rode one, very nice bike. The guy who did it didn't say it was very hard.

I know the 1000 8v engines into the first gen 750s is very easy to do. I have done a few, didn't beef anything up and it worked fine, but I'm not riding it hard at 150mph, either.

 

[Nessism]

http://www.diablocycle.com/GS750-Lower-Engine-Brackets-Unfinished.html

I believe it's the lower mount that's different. The above link is for conversion motor mount plates. Some guys just leave the lower mount off though.

Some beefier forks and an aluminum 1100E swingarm w/nice shocks would enhance the swap nicely.

 

[hillsy]

I did a few swaps some years back when I worked in a shop (1100 Katana motor into Kat 750 frame.....circa 1982 vintage). Yes - everything lines up except the bottom engine mounts (underneath the crank). Pretty easy to cut some new ones out.

I think you have to trim the sprocket cover a bit on the 1135 motors but they slot straight in as well.

 

[Jedz123]

Done it... It's actually pretty easy, Just be sure you match up the carbs with your engine. Great time to ensure the new motors valves are in check. Killer powerful. A bit too much on old school GS750 suspension and braking bits but hey to each their own. You will need to fab custom plates... Easy

I also swapped out my 750 oil pump gears too... Just before I pulled the basket out...

I Used a Dyna-S and used the stock 750 coils.

 

[blowerbike]

it's a bolt in except for the center bottom triangles...
either leave them off or fab a pair of off center triangles.
the 750 does not have a cross brace on the front down tubes...depending on HP you can add the cross brace.

 

[headsbikesmopars]

Sounds like an interesting and fun project. I will have to do this. Thank you all for your responses.

Terry

 

[madmikeracing]

Our old drag bike was built on a 750 frame. We did have all billet engine mounts and engine threaded for bolts. This was so long ago mid eighties! It ran straight had a puppet swingarm and some chassis mods. If I remember correctly I also had the only round swingarm at attco and norwalk back then that I saw. That chassis was perfect ran 1.14 s in the 60 and our best back then were 8.54s at 15- plus in quarter. We used the 750 frame because we had bought a 750 race bike from Vance and Hines at that time. (which blew up in spectacular fashion shortly afterwards!!) The 1100 engines fit perfectly .