I originally did a conversion for the GL1000 to hydraulic clutch, using GL1200 Aspencade clutch master and slave cylinders, pipework and an '84 GL1200 clutch cover.
(An '84 cover HAS to be used. This is a one year only cover and quite rare but the later covers have a bolt spacing completely different to the GL1000.)
Well, although it worked fine I was less than happy at the results, as the object of the exercise was to lower the lever force needed.
When I was over at Cyborg's in the States last year, we did some experiments and I found that the whole clutch from an '84 / '85 1200 would JUST go in! (in theory, as it was a lash-up job just to test some ideas out).
On arriving back here, a complete '84 GL1200 clutch was bought to do the full conversion.
OK, so why would I want to do this? Here's the reason.
The black part in the centre is a diaphram spring. This method of springing allows high clamping pressure with low actuating pressure.
This is a BIG clutch! 1200 left, 1000 right.
All the plate thickness measured up OK but I had
to use the hated 'B' plate as I didn't have spare
plain ones. This will be dispensed with later.
The 1200 basket has one more tooth on the
oil pump drive sprocket
The oil pump chain is the same for all the GL1000/GL1100/GL1200 which means that the GL1200 oil pump sprocket has to be used as it's smaller by one tooth! GL1200 left, GL1000 right.
That means that the GL1000 oil pump will be overdriven by my reckoning by about 12% which should help the lubrication a bit.
The GL1200 pressure release plate has an open
bearing to allow the normally fitted long guide pin
to go through. This hollow guide pin actually goes
right into the end of the mainshaft and feeds
extra oil to the clutch.
The GL1000 mainshaft instead has a plug in the end,
with a squirter hole. I didn't want to mess with the
mainshaft so I used the GL1000 push rod cup instead
which needs to be swapped into the GL1200 lifter plate.
The GL1200 pushrod has to be shortened down
The correct locking washer for the GL1200 clutch locates on the nib above the screw. I could not find a new one over here so the clutch pressure plate was drilled and tapped for a screw and the GL1000 lock washer used.
A tight fit! Actually, it's not quite as tight a fit as it looks. There is some overlap of the gasket which, when trimmed away, leaves a gap of 2mm-3mm between the outer clutch basket band and the cover.
All buttoned up!
All ready to go back into the bike, having checked that nothing is fouling on the covers. There is one drawback immediately apparent from this conversion. There is no way that ANY clutch work can be done with the engine in the frame. It is not even possible to remove the slave cylinder!
This would be a great conversion too for anyone with a sidecar or someone who is pulling a lot more power out of the motor.
One more thing. The clutch design changed for the 86 / 87 1200 to a ribbed type of clutch basket with altogether different friction plates. This basket looks as though it may be slightly bigger from pictures; not sure on that as we didn't have one to try but if it is, it won't go in!
This conversion would also work on the GL1100. The GL1100 clutch is different again but uses the same hollow guide pin as the GL1200, so may be more straight forward but I haven't tested this.