GS1100 16v cylinder spacing - not carb spacing

[Senlisian]

Hi there folks, I've been trying to find out for some time what the outer and inner cylinder spacing is for the 16v GS1100 but cannot find this info anywhere.
I would like to stress that it's not the carb spacing but the actual cylinder centre spacing I need to know.
If anyone can tell me these measurements I'd really appreciate it, thanks.

 

[rapidray]

Hi there folks, I've been trying to find out for some time what the outer and inner cylinder spacing is for the 16v GS1100 but cannot find this info anywhere.
I would like to stress that it's not the carb spacing but the actual cylinder centre spacing I need to know.
If anyone can tell me these measurements I'd really appreciate it, thanks.

For what reason if I may ask? I believe 1 & 2, and 3 & 4 are on 95 or 96mm spacing. Ray.

 

[Senlisian]

Hi Ray, thanks for your quick reply! In that case I think it must be 95mm. The only info I've been able to glean is the possiblity that the outers could be 95mm but it was written in Japanese so I couldn't be certain it was the bore spacing being quoted. Still no idea what the spacing is for cyls 2 & 3 are though...
The reason is an idea I have to maybe build a hybrid gs/gsxr engine for post classic racing using the cases of a gsxr engine and the barrels & head of a 16v gs1100.
This would give the character & soul of an air-cooled GS combined with the narrow cases & plain bearings of the GSXR bottom end.
The biggest potential problem I can see is that it would be illegal due to the fact that 1/2 the engine is from a different period (notwithstanding the cost of the mods needed to make it work, but I'm working on fundamentals here, less so financial practicalities & time considerations).
I know GSXR heads have been grafted to GS engines successfully but this doesn't interest me so much knowing that GS heads can produce at least the same power output as GSXR items. It seems to me that the biggest change between the two is the SACS cooling system which is effectively disabled on the GS application. Also I have a feeling that it has been said that some of the head studs are located differently - I'd be interested to know if this is correct or not.

 

[Senlisian]

PS. I've just noticed you seem to have an addiction to speed...

 

[rapidray]

Are you in the USA? If so, call me at the # I am PMing you.
Ray.

 

[GregT]

For what it's worth I've seen it done the other way round. GS1000 top end on GSXR cases and crank. Done to get around capacity rules for speedway TQ's - and to get a lighter, plain bearing bottom end.

Good luck with your project.

 

[Senlisian]

Are you in the USA? If so, call me at the # I am PMing you.
Ray.

Hi Ray, replied by PM but not sure if it was sent. I'm in France so 9hrs ahead of you. Could I call you on Saturday?

 

[Senlisian]

For what it's worth I've seen it done the other way round. GS1000 top end on GSXR cases and crank. Done to get around capacity rules for speedway TQ's - and to get a lighter, plain bearing bottom end.

Good luck with your project.

Hi Greg, this is EXACTLY what I'm thinking of doing!

 

[GregT]

Hi Greg, this is EXACTLY what I'm thinking of doing!

From your explanation I was under the impression you wanted to put a 16v 1100 top end on the GSXR cases. Stud spacing is the problem I'd think. The 8v top end on early GSXR cases involves quite a bit of work to my knowledge.

And as a builder of post classic race bikes and motors myself, I don't know of a rule set anywhere in the world which would accept the hybrid motor as a "period" item.

 

[Senlisian]

Greg, sorry I understood GS1000 to be the US spec 16v Katana engine.
I know the stud locations are different between 8v & 16v engines, but not sure of differences between 16v & GSXR engines.
Pretty certain you're right about regulations for eras as well. The most recent major component will decide the class to run in, even if it's only 1/2 of the engine
So, this is probably academic now, but I'm still keen to know what's involved in a 16v GS top end on a GSXR bottom end.

 

[GregT]

Your first step, unless Ray has definite information, is to compare base gaskets. This will tell you stud spacing at least.

 

[Senlisian]

Ray, I'm not sure if you've got my PM's - I can't see any sent mails gone out...
Could you please PM me with a time/day that suits you for me to call, thanks.

 

[rapidray]

The cylinder stud spacing IS the same on the GS 1100 & the oil cooled GSXRs. Call me between noon & 2 pm, Pacific time.
Ray.

 

[Senlisian]

Ray, thanks a million for your info and help! I didn't manage to get hold of you by phone again today but with this info you've provided me I now know that if I do decide to follow this idea through that these major components will fit together.
As I said at the beginning, I couldn't find the information I needed anywhere on the internet after some months of searching so I'm really grateful for your assistance.