Engine locked up on the highway

[1983lux]

Went to town on it and have the motor out. I’ve found a 1981 gl1100 motor from a reputable guy that rebuilds tons of 1100s and has a pile of 1100 parts.

My plan is to use my 75 carbs and rear cover, put the left 1000 head on the new motor with the old ignition.

The question is, are 1100 heads the same at the base? Since my right head is toast, I was thinking to put the 1000 right cam and carriers (which are still ok) in an 1100 right head he’ll give me with the motor. Will this work? Or do I need to find a 1000 right side head?

Also, should I use 1000 or 1100 new head gaskets, or are they the same?

Thanks!

IMG_5109.jpeg

[robin1731]

You can't swap the cam carriers from head to head. They are machined as a unit. Use the carrier for the matching 1100 head but use the rocker arms matched to the 1000 cam.

Use the head gasket that matches the size of the pistons.

[1983lux]

Thanks Robin! Good to know, I've got a GL1000 gasket but maybe should order an 1100 one. As far as timing marks, does the GL1100 have the F1 mark at 5 or 10 degrees after TDC? With my 79 block which is now toast and 75 cams, I had to time it between the T and F marks. Same for GL1100 flywheel?

[robin1731]

Personally I would get the Randakk timing wheel and time it off of the cam. They sell 2 different wheels. Get the one for the advancer unit that you have.

This is the one for 75-77. https://www.randakks.com/randakks-amazi ... wheel.html

You'll need to know TDC for #1 piston but that can easily be done before you install the heads.

[Sidecar Bob]

I read there’s issues with them being overly low geared with the 1000’s drive system.

I ran a '79 GL1000 engine in my '83 GL1100 with the 1100's final drive for 22 years. The combination of 1000 engine & transmission and 1100 final drive resulted in overall gearing more than a gear higher than stock, which was wonderful on 2 wheels - lower RPM the highway and great mileage.
I would expect that a 1100 transmission with a 1000 final drive would be at least a gear lower with an increase in fuel consumption and significantly higher RPM (imagine running in 3rd or 4th gear on the highway).


FWIW, when I added the sidecar it struggled to pull away briskly, especially when uphill with a passenger so I eventually found an '82 GL1100 engine for it and it does much better now.

[1983lux]

Thanks WF, a fair warning! I had no luck finding a gl1000 anywhere close to me, and was too tempted to have the bike running during the short riding season up here, so did the 1100 swap over the weekend.

It’s an 81 block. Put my 1000 left head with dyna III on it, and my 371 cam in the 1100’s right head since mine was chewed up. Has the 1000 rear cover, but with the 1100’s clutch cover. Running my 75 carbs. Had to mod my clutch cable slightly.

It definitely pulls great in the lower gears. At 75mph, I rev at about 5000 rpm which isn’t terrible. These would be perfect gears for a city or cafe racer bike that rarely goes above 60, fun for scooting around. I can cruise with it this way just fine, but considering that maybe I could respoke my rim to 18” next time my rear tire wears out? Or maybe I’d be wise to start looking for a new GL spoked wheel now as one of my wheel bearings is held in by fast metal retaining compound and not sure how long that’ll last.

Overall, happy to be back on the road!

[Fred Camper]

Fast progress for sure. You have pit crew speed. Nice to see her running already. There are some 18 inch lesters out there if you can find one.