I'm sure this has been mentioned before but here goes anyway.
When I was dismantling the 76 engine, in the filter trap and around it there was loads of clutch friction material, along with piles of other crap.
When I dismantled the clutch, here was the reason!
Theres a bit more info with the pics in my Photobucket album.
In the middle of the clutch pack there sits the most horrendous piece of engineering which Honda call 'Plate B'.
It's a clutch damper, two plain plates which sandwich a number of spring steel strips between them to give a cushioning effect to the clutch action.
The steel strips are held by TINY BRASS rivets, one end of each strip rivetted to one plate and the other end to the second plate.
As the strips flex the rivets are either worn through or pulled out of the plates. If you check the above pic you will see the result.
In these pics you can see the results of the one strip which came completely out.
This one shows the components.
Obviously bits of rivet could easily get into the clutch oil pump and cause all kinds of damage, the errant steel strip could jam the clutch or the oilpump drive chain etc.
I can't even see the reasoning behind having this abomination. There is enough slack in a chain primary drive to give some cushioning plus the output shaft has a spring shock absorber, so this just seems like overkill to me.
So, if you've got to do the clutch, do yourself a favour and heave this thing into the nearest bin.
Of course, that then leaves the clutch pack short of the thickness of the damper.
Easily remedied! The plain plates are just a tiny fraction thinner then the damper, so purchase an extra plain plate, but be careful where you fit it.
It needs to go here, directly onto the spring carrier. This is double good as it provides a steel surface for the first friction plate instead of the alloy of the spring carrier.
There's a bit more info with the pics in my ENGINE REBUILD TIPS, page 4.Addendum
Something interesting came up whilst I was over in the States this year. In the course of replacing the clutch on one of his engines, Steve Seamans noticed that the Plate B that came out had internal teeth on both the plain metal side plates!
This is obviously what should have been the correct design right from the beginning, as now the spring plates and rivets only have to provide the cushioning effect that they were intended for, and do not have to transmit any torque at all.
It would seem that Honda realised that there was a problem and brought out a modification but I have no idea as to when this was instigated. I have three GL1000 clutches sitting here; all three have the original single toothed B plate.
So if you have one of these modified plates, you may want to keep it, except for one thing; strangely, the rivets that hold the spring steel straps are still made from brass in the later one. Not the best engineering solution!
Steve also found that doing the conversion as outlined above resulted in his clutch having an unacceptable rattling when the lever was pulled in.This is probably caused by the plain plates vibrating against the alloy when the spring pressure is released but I'm at a loss to explain why his should be noisy and mine quiet. It may be due to individual clearance settings (I guess you could always tell people that you have a Ducati clutch fitted!