GS1100g top end on GS1000

[robertob]

I know this has been brought up before, but I can't figure out if I can run a GS1100g barrel & pistons on a GS1000 8-valve. I know the G has a longer stroke (by 2mm, I think), but is the difference in the pistons, rods, cylinder or all three?

I've got a set of GS1100G cylinders sitting here that I'd love to use if I can...

 

[phaserburn]

Hey,

I am actually looking to do the same thing.

Have a look here:

http://www.thegsresources.com/_forum/showthread.php?t=1210

 

[first timer]

I have heard the 1100g head can fit on the 1000 block.

 

[robertob]

So I did some measuring just to see how it works out.

Catalog data:

GS1000 = 70mm bore X 64.8mm stroke, 997cc
GS1100g = 72mm bore X 66mm stroke, 1074cc

Measured data:
GS1100 = 72mm piston, 18mm pin, 26mm deck (center-top), 88mm cylinder height
GS1000 = 70mm piston, 18mm pin, 26mm deck (center-top), approx 88mm cylinder height (don't have one to check)

So it looks like the GS1100 cylinder will work, but I'd hone it and run new rings to get the best ring seal.


The resulting displacement will be only 1050cc, though, so I don't know if it's worth it. I wonder what compression is?

 

[srsupertrap]

So I did some measuring just to see how it works out.

Catalog data:

GS1000 = 70mm bore X 64.8mm stroke, 997cc
GS1100g = 72mm bore X 66mm stroke, 1074cc

Measured data:
GS1100 = 72mm piston, 18mm pin, 26mm deck (center-top), 88mm cylinder height
GS1000 = 70mm piston, 18mm pin, 26mm deck (center-top), approx 88mm cylinder height (don't have one to check)

So it looks like the GS1100 cylinder will work, but I'd hone it and run new rings to get the best ring seal.


The resulting displacement will be only 1050cc, though, so I don't know if it's worth it. I wonder what compression is?

Can anyone explain the 26mm deck (center-top) measurement listed above?

 

[salty_monk]

Centre of the pin to top of the piston?

 

[srsupertrap]

Dan, I think you are right.

I went over Tom's (Tkent02) garage and we took some measurements of my GS1100G and one of Tom's GS1000E cylinder block. The cylinder height was measured from the base gasket surface to the head gasket surface with a digital caliper. Note: The GS1100G measurement includes the thickness of the base gasket (.35 - .50mm). It's stuck on pretty good after 27 years

Measured Data:
GS1000E: 86.8 to 86.9mm
GS1100G: 87.4 to 87.5mm with Gasket

 

[7981GS]

Two threads running at the same time on the same subject?
http://www.thegsresources.com/_forum/showthread.php?t=149275

Dan

 

[srsupertrap]

No, I searched and found both and decided to resurrect them since neither thread came to a conclusion. I have a GS1100G head and like Kochic I am interested in using a GS1100G cylinder for a larger bore Wiseco pistons, 73.5mm in my case.

7981GS,
Can you take a height measurement of one of your GS1100G cylinders with a digital caliper or a micrometer? My measurement above includes the base gasket and I am interested to see how your measurement compares to the GS1000E cylinder measurement of 86.8 to 86.9mm. I took the measurement at the ends of the cylinders.

TIA
Steve

 

[Guest]

No, I searched and found both and decided to resurrect them since neither thread came to a conclusion. I have a GS1100G head and like Kochic I am interested in using a GS1100G cylinder for a larger bore Wiseco pistons, 73.5mm in my case.

7981GS,
Can you take a height measurement of one of your GS1100G cylinders with a digital caliper or a micrometer? My measurement above includes the base gasket and I am interested to see how your measurement compares to the GS1000E cylinder measurement of 86.8 to 86.9mm. I took the measurement at the ends of the cylinders.

TIA
Steve

Gs1085 -73mm ,73.5mm is a 1100kit.

 

[srsupertrap]

Gs1085 -73mm ,73.5mm is a 1100kit.

gshub,
You are right those are pistons sizes. I am actually interested in the GS1000 & GS1100g cylinder height (not bore) measured from the base gasket surface to the head gasket surface with a digital caliper.

 

[7981GS]

gshub,
You are right those are pistons sizes. I am actually interested in the GS1000 & GS1100g cylinder height (not bore) measured from the base gasket surface to the head gasket surface with a digital caliper.

I just saw this, I'll try to measure them for you when we get back from Church.

Daniel

 

[7981GS]

Deck height, is .020 higher on the 1074 cylinder Vs. the 997 cylinder.

Daniel

 

[gs1428]

bolt it togather. done many of them. big incrae for little effort

 

[Guest]

People are using our 75 mm pistons with the 1100g set up. Bores right in. 1166cc

http://gszone.biz/

 

[7981GS]

Excellent idea!
I went with the 74mm bore...

.015 off the top of the cylinder and a .005 base gasket also

Daniel

 

[Nessism]

When I first bought my latest 1000S it had a 76mm piston kit installed (with issues) and some high duration cams (which reduces cranking pressure). Jabbing the starter button resulted in a very unpleasant "crack" noise as the starter clutch complained about the task of turning this beast over.

For you guys "going big", that starter circuit mod suggested by Ray/Pos is worth investigating in order to save your starter clutch, and your wallet.

 

[srsupertrap]

When I first bought my latest 1000S it had a 76mm piston kit installed (with issues) and some high duration cams (which reduces cranking pressure). Jabbing the starter button resulted in a very unpleasant "crack" noise as the starter clutch complained about the task of turning this beast over.

For you guys "going big", that starter circuit mod suggested by Ray/Pos is worth investigating in order to save your starter clutch, and your wallet.

IMO it's not a matter of even going big, I installed the smallest Wiseco 1085 kit, andrews S1 cams & VM29's and that was enough to induce the starter clutch whack in my GS1000 when the temperature dropped into the 40's. The GS starting system like the charging system is nominal at best, add any additional load and the starting system won't handle it. My half baked solution through the 80's, 90's, 00's on was to install a 16 Amp Harley battery were the airbox resides. This is actually worked pretty good from a brute force solution standpoint but I never liked the idea of the battery weight being placed high up and it still occassionally kicked back when cold. Since 2007 I have incorporated the starter circuit mod from Ray/Pos were I can spin the engine in the Off position and then add ignition by switching to run. I was hoping this would solve the problem once and for all but when it's cold that stock 14A battery does not have enough Omooph to turn it over the engine fast enough to totally eliminate the starter clutch kick back. I swear I have even experienced a starter clutch kick back when jumping the GS from a car battery when the temps were in the 20's.

When I first heard that starter clutch whack I thought I shredded something for sure. I replaced the starter clutch rollers, inspected the teeth (they were Okay) and bolted it back together. That was 1985 and 35K later I am inclined to say it's another inherent design flaw you will have to live with if you go bigger, install bumperer cams and live in colder climates

 

[mlinder]

I know this has been brought up before, but I can't figure out if I can run a GS1100g barrel & pistons on a GS1000 8-valve. I know the G has a longer stroke (by 2mm, I think), but is the difference in the pistons, rods, cylinder or all three?

I've got a set of GS1100G cylinders sitting here that I'd love to use if I can...

The stroke is determined by one thing, and one thing only: The crank.

It's the distance between the center of the crank pin at TDC and BDC.

Doesn't matter how tall your pistons are, how long the con rods are, the stroke length will be the same, if they are connected to the same crank.

That's not to say that if the pistons were proud of the cylinder deck that you couldn't cut them down to fit, or use shorter con rods, but pistons travel, or stroke length, would remain the same.