Project GS1100 'S'

[Muppet]

I've just bought myself an engine from an R1100S. It's supposed ot have done just 14,000 miles, and if my research is right comes with a healthy 98bhp So, I'm going to stick it into my 1100GS and enjoy a near 20% increase in power. I know the torque & power delivery may be different, but I use my GS so little off road that it doesn't matter.

I picked up the engine yesterday, and on first sight there are just 2 noticeable differences. The exhaust ports are slightly different and the flywheel/clutch assembly is different.

It came complete with headers, which is good as they run either side of the bike as opposed to joining down the right side as on my GS. I may need to do some fabrication but I will use the 'S' headers as the ports are different.

The flywheel/clutch difference should be easily addressed by swapping flywheels from my GS onto the S engine when I make the change.

All the mounting points for the frame/subframe are the same, but the airbox is a different shape. Again, I should be able to just use the GS one as the inlet tubes look the same.

The engine came complete with all electrics including injectors and ECU, starter motor and alternator. So, once I've done the swap I shall have a complete 1100GS engine & gearbox (already had that) whic will form the basis of another project, namely my take on an HP

Stripped down 1100GS with minimal extras to keep the weight down and possibly a telescopic fork conversion. But don't hold your breath, the engine swap will no doubt take me most of the winter, I've then got a VFR800 to rebuild from scratch before I tackle the HP project. Should keep me busy for a year or 5

If anyone has any comments/suggestions I'd be happy to hear them, I'll update this thread when I start, which won't be for about another month yet.

 

[Schwarz Baron]

No Tips, but good luck, can't wait to see and read about it

 

[Steptoe]

You might be able to fit an 1150 y piece on your S exhaust, it's the same 2 into 2 - maybe easier than making your 1100 exhaust system fit

 

[DrAlf]

Just fit the S heads and headers. AFAIK that's where the extra power comes from. Be a lot easier. You can then fit the GS heads to the R1100S engine and use that as the start of the HP project. Just an idea.

 

[Muppet]

Just fit the S heads and headers. AFAIK that's where the extra power comes from. Be a lot easier. You can then fit the GS heads to the R1100S engine and use that as the start of the HP project. Just an idea.

Well, that would make things a whole lot easier! Thanks for thatDoc, but I have one small problem - which I suppose is a confession really. After my gearbox failed in Spain and I fitted the one Vern kindly sold me (at a bloody good price I have to add, thanks Vern ), I was a little over enthusiatic with tighening up the right hand front subframe bolt on the engine. The one just near the main telelever bolt. I could feel it start to 'go' for want of a better word, in other words it was beginning to strip the thread. I know I can get it helicoiled, but that's pretty much an engine out job AFAIK, so when I saw this 'S' engine I though AHA! Here's an opportunity to cure that at the same time and have a bit more poke for not too much money.

The bolts still there, and doesn't feel like it's moved at all but it's niggle I'd rather put right over the winter. Besides, the 'S' engine has done 40,000 miles less than my original one, so I may as well whack it in as I intend to keep this bike until I can't ride the thing anymore.

But thanks for the tip, could be useful for future projects.

 

[DrAlf]

Fair enough then. Sounds like a good project - keep us posted and take lots of pix

 

[Paul Young]

ISTR that the 1150 was created by using the R1100GS bottom end, matched to R1100S heads & R1200C barrels/pistons (or was it the crank?).

Anyway, the power/torque of the R1100S was 98bhp/64ft-lbs at the crank & with the higher top speed being the result of the FD gearing & from being less of a barn door than the GS. An 1150GS can get the same (or better) power/torque quite easily & putting the R1100S heads on your 1100GS would definitely be a step in the right direction...

BTW, 1150GS headers, Y piece & silencer would then fit. 1100S headers won't mate up to a GS cat' or Y piece.

Sounds like you'll have some fun...