GL1100 Engine2
GL1100 Engine2

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GL1100 Engine2

Fitting hydraulic GL1200 clutch into GL1000

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 Doug's workshop 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 toothed 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.

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

to 42.5mm.









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 guide pin as the GL1200, so may be more straight forward but I haven't tested this. 

diaphram spring (Small)
big clutch! (Small)
clutch packs (Small)
oil pump sprockets (Small)
lifter plates (Small)
lock washer (Small)
tight fit! (Small)
1200 rod cut and ground to this size (Small)
ready (Small)

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J G Evans