Engine Choice: 1100 vs. 1150

[Anonymous]

So if one were to be building a custom sport bike chassis for a GS engine (hypothetically, of course ), which would be the better choice between the 1150 and the 1100? I am thinking the 1150 simply because of the extra displacement and power potential. They DO vibrate, though, from all the comments I have heard/read about it on this forum. Any other reasons to choose the 1100? Weight differences, overall dimensions, anything else?

Regarding power, I am thinking in terms of a stomping street motor with tons of torque and 130-140rwhp. For this I think the 1150 is the better choice. Any other opinions?


Mark

 

[RacingJake]

Seems to be more piston kits for the 1100 18mm crank than the 1150 20mm ones. But the 1150 head is alot better for power.

Either way 130 hp is easy with a big bore kit and carbs. Most likey your biggest problem will be traction with the oem tire, you may need to go big in that area too.

 

[Anonymous]

Most likey your biggest problem will be traction with the oem tire, you may need to go big in that area too.

Jake, you never noticed the "custom frame" part of my question. This will have 3.5F/5.5R 17" rims and radial tires. A sticky 180 or 190 rear will easily keep that in check. Of course, then it will wheelie, but that's the way it goes...

Seems to be more piston kits for the 1100 18mm crank than the 1150 20mm ones.

I have seen that. The most I will want is an 1197 Wiseco kit, though, and that is not a problem. I don't think anything larger on the street is a good idea, just becasue of the heat issues. And an 1197 motor with G3 cams, 36mm flatslides and a good pipe will easily achieve my power target with a nice fat torque curve to pull it along.


Mark

 

[Billy Ricks]

If I remember correctly Bimota used the 1150 in on of their moels back in the mid '80s.

 

[RacingJake]

I'd go with the 1150 engine, since all you got to do is bore the cylinders 2mm to reach 1197cc. With a 1100 resleeving is required.

Sounds like you got a game plan already :twisted:

 

[rosco15]

1150. You can go 1260 with stock sleeves and the head is better.

 

[oldschoolGS]

It is amazing how dated the Bimota looks now. I can remember drooling over them in the late 1980's. Today's liquid cooled stuff is light years ahead of that design. Makes you wonder what the future holds 15 yrs from now. Ride On, Ed.
1983 GS750ED (still in progress)

 

[Billy Ricks]

It is amazing how dated the Bimota looks now. I can remember drooling over them in the late 1980's.

Thought the same thing myself. Still looks like a pretty sweet chassis though.

 

[shaftzuki]

It is amazing how dated the Bimota looks now. I can remember drooling over them in the late 1980's.

Thought the same thing myself. Still looks like a pretty sweet chassis though.

I sure wouldn't "kick her out of the garage" :wink: 8)

 

[marcovandevelde]

Have to agree to go for the 1150 with 1260 overbore. The engine looks nicer (I think) and has some niggles like clutch-basket play solved. Cranck's welded too, not always the case on 1100's.

Good luck, Marco.

 

[Anonymous]

You will be lucky to find either engine without buying a whole bike. both can be turned into animals. the 1150 has a stronger crank though

 

[Anonymous]

You will be lucky to find either engine without buying a whole bike.

I expect to have to buy a bike and part it out. This is in the future, though. I still have some little things to sort on my 1100E before I go nuts and commit to a project of this magnitude.

Thanks for all the replies, they confirmed what I was thinking.


Mark

 

[Anonymous]

One last question - are the 1100 and 1150 dimensionally the same regarding motor mounts and external envelope dimensions? That is, can I start measuring my 1100 motor up to begin laying out a chassis? From what I have seen they have to be very close, because so many parts interchange and they look so alike. Does anybody know different?


Mark

 

[rosco15]

I know the 1000 and 1100 are different. I always thought the 1100 and 1150 were the same. I'm Not 100% sure and I have never worked on an 1150. I just use the parts on my 1100.

 

[Hap Call]

One last question - are the 1100 and 1150 dimensionally the same regarding motor mounts and external envelope dimensions? That is, can I start measuring my 1100 motor up to begin laying out a chassis? From what I have seen they have to be very close, because so many parts interchange and they look so alike. Does anybody know different?


Mark

It's been my understanding that they are the same external dimensions.


Hap

 

[lecroy]

I run an 83 1100 engine in an 84 1150 frame. The mounts are the same between the two. The 84 frame is a bit higher over the top of the head which is nice when it comes time to swap engines. No need to pull the valve cover off.

 

[Anonymous]

I run an 83 1100 engine in an 84 1150 frame. The mounts are the same between the two.

Awesome. Thanks for the info Lecroy, that is just what I wanted to hear. I will use my 1100 motor as the basis for my layouts until I find an 1150 to work from.

Thanks to all for the replies.


Mark

 

[gsBert]

i have an 1150 engien in a 1981 1100 frame.
while the mounts line up just fine, here are a few concerns:
- the engien doesn't slide in with the valve cover on it. (that camchain box on top...)
- the left side of the engine (magneto) sticks out more.

i thought the 1150 motor already puts out close to 130 hp stock, doesnt it?

 

[Anonymous]

the engien doesn't slide in with the valve cover on it. (that camchain box on top...)

No problem, Bert. I am working on a custom spine frame that will not require sliding the engine in at all, it will be hanging from the spine and will simply lift into place from below.

I can't pull the valve cover off my 1100 without pulling the cover off the camchain box first, anyways, so it sounds like they are pretty close in that area.

i thought the 1150 motor already puts out close to 130 hp stock, doesnt it?

Maybe in the advertising brochures. RWHP for a stock 1150 would be maybe 100-105. With pipe/pods/jet kit/degreed stock cams I would expect 115-120rwhp. With 36mm flatslides and G3 cams I would expect a touch over 130rwhp. Add an 1197 Wiseco kit and it should be close to 140rwhp, with over 80ft-lb of torque. Perfect!


Mark