GSx 1100 Cylinder head/ barrels/ crankshaft compatibility

[scotgary]

Hi guys,

Looking through my spares room got me thinking  ( could be dangerous! )

Is the head off a gs1100 a direct swap onto a gs1150?

also,

Will the crank and barrels off of the gs1150 drop into the GS1100 cases?

 

Thanks,

[Duckndive]

40 minutes ago, scotgary said:

Hi guys,

Looking through my spares room got me thinking  ( could be dangerous! )

Is the head off a gs1100 a direct swap onto a gs1150?

Thanks,

Assuming you mean a GS1100 "4V" motor

Yes it fits but you will need to use some of the GS1100 studs and associated hardware "nuts and washers"

A look in the Parts Pages on Alpha Sports will reveal the parts and differences

Quote

Will the crank and barrels off of the gs1150 drop into the GS1100 cases?

Again assuming its a GS1100 "4V"

Yes the crank fits the cases but will need the matching clutch basket as the Primary Ratio is different

You will also need the matching alternator to fit the larger taper of the GS1150 crank

Its also advisable to use the GS1150 starter and intermediate gear if you intend to use the 1135cc block

Yes the Block will also fit but you will need to open up the crankcase mouths to accommodate the thicker liners of the 1135cc Block

 

Edited November 19, 2018 by Duckndive

[johnr]

also if youre mixing and matching the 1075cc gsx engine has 18mm small ends, th 1135cc gsx engine has 20mm small ends, so whilst you can swap stuff between cases, if you want to run an efe crank, then you need to use efe pistons with it. and vise versa.

[cnap504]

Sooooo, how much trouble is it to install a 1150 head on to an 1100 engine?  Would the 1100 pistons dome, valve reliefs, and pin height be compatible?

[Arttu]

If I recall correctly you need to change the head studs too. Otherwise it should be just bolt-on. 1150 intake valves are 1mm bigger but I think that should be still ok with reliefs on the 1100 pistons.

To be clear, I have never done exactly this swap but I have played quite a bit with both engines and don't see any problem there. And I know it has been quite popular mod back in the days.