cylinder heads

[jbombyk]

Are the head on aGl100 and a GL1100 interchangable?

[Old Fogey]

Not from a GL100!
GL1000 and 1100 right hand heads are interchangeable. The left hand heads are also but with the proviso that the 1000 has the rear of it machined for the contact breaker assembly; the 1100 does not.
So, on an 1100 you can use the R/H 1000 head with just an empty c/b box and using the 1100 ignition system, or use the entire 1000 head and ignition system and bypass the 1100 electronic system
On a 1000, you would have to find a way to have the 1100 head machined for the contact breaker system.

[jbombyk]

thank you I wokeup in the middle of the night thinking about this because they looked so similar.

[Old Fogey]

Not from a GL100!
GL1000 and 1100 right hand heads are interchangeable. The left hand heads are also but with the proviso that the 1000 has the rear of it machined for the contact breaker assembly; the 1100 does not.
So, on an 1100 you can use the R/H 1000 head with just an empty c/b box and using the 1100 ignition system, or use the entire 1000 head and ignition system and bypass the 1100 electronic system
On a 1000, you would have to find a way to have the 1100 head machined for the contact breaker system.

Sorry, mis-typed: "So, on an 1100 you can use the R/H 1000 head with just an empty c/b box" should obviously been L/H head. You could also simply make up a blanking plate instead of using the empty points box.

One other point. All these heads have the cam carrier bolted to them before they are machined, so they become one unit. There is NO separate part number for the cam carrier. So keep the two parts together.