GS1000 head on a GS1100G?

[robinjo]

Fitting a GS1000 head on a GS1100GK?

Would it be possible? 1100G are based on the old 2-valve design right, even if it is a '84.

[first timer]

i belive it is more perfered to do it the other way, the 1100gk head should fit on the 1000 which is better cause it has bigger valves and D shaped exhaust ports.

-ryan

[focus frenzy]

it may be possible, the part numbers are differant, and the combustion chambers will probably be a bit larger to acount for the larger cylinder bore.
you will need to take mesurements to make sure the 1100 pistons will clear the combustion chambers.

best case is it clears and you get a higher compression ratio.
worse case is the outer edge of the pistons wont clear the outer edge of the combustion chamber.

also the valves are the same size (same part numbers between 81, 1000 and 84, 1100)
the exhaust cam is differant but they interchange.

[Hoomgar]

It depends on what year GS1000 head. If you use an 80 GS1000 head then you will have the same size ports and carb inlets. You have to use the cylinder too though because the bolt pattern is different.

Here is the added bolt that the 78 and 79 don't have.

[Hoomgar]

Here you can see the size difference in the carb intakes too.

Here is the 78/79 style with the vm26ss carbs:


Here is the 80 with the 34mmcv style carbs:


You can see they are bigger.

[Flatline_Racing]

both my 1000's made in late '78 have the extra bolt. Bike bandit shows the extra bolt on the s and L models for '79

[Hoomgar]

both my 1000's made in late '78 have the extra bolt. Bike bandit shows the extra bolt on the s and L models for '79

The 78 didn't have that dood that I know of? All that indicates is that your's has already been replaced and is not the original most likely? Anyone else know for sure? I thought all the 78 heads and cylinders were the same? In 79 they introduced new models and some design changes. Some of the 79's did have it. But the ports are still smaller. It's an 80 head he wants to do it right.

[robinjo]

Thank you guys!