B31 1958 Clutch arrangement

[pete lafeet]

I hope someone can help with this please. I am having clutch slip which I have tried unsuccessfully to adjust away. So I stripped the clutch and found there is only 4 friction plates, I believe 5 plate is the correct number. There are 5 plain plates which I think is correct. Can i just add a friction plate to the end of the stack? Do I start with a plain plate and if so is it correct to end up with a friction plate next to the pressure plate.

[idie]

That is the right amount for a B31. If you want a 5 friction plate clutch you will need a deeper clutch drum. One off a B33 or an A10.

[JulianS]

Cross section of the alternator B31 clutch.

[idie]

Ah you didn't say it was an alternator clutch which is a Triumph one.  Are you assembling it correctly. It may look as if the drum is acting as a plain plate. You start with a plain plate then friction plate and so on. If still having a problem you will need a deeper drum from a larger capacity bike to get the extra plates. Make sure it is one with the built in rubbers.

[pete lafeet]

Thanks everyone. The bike has an alternator and looks like the clutch has the cush drive in it. Whats puzzling me is that the spring nuts are way down the screws, nowhere near flush or just under. Ill try to put it back together and post a photo to show what I mean. Sorry to labour the point, I'm new to classic bikes, but everything I have found, Haynes Draganfly etc states 5 friction plates for my year of B31.

[JulianS]

Is there sufficient space in the chainwheel and on the drum to take another plate? If yes you could try it but you need to be sure it will be retained within the drum and not slip out of place when the clutch is withdrawn.

The alternator A10  models of the time used a similar 4 spring clutch but with a deeper chainwheel and centre to take its 5 bonded and 6 plain plates. The same bonded and plain plates were used for both models.

[pete lafeet]

Thanks JulianS you are most helpful. I don't know for sure if there is enough space for another plate. I don't have enough experience with this type of thing yet. The extra plate would be a bonded plate I assume, which would end up next to the spring plate. Would that be ok? Also I have totally confused myself looking at the parts list for this clutch on Draganfly. There seems to be two spring cups and different springs although my springs look like the 5 plate clutch springs but the spring cups look like the 4 plate type?

[JulianS]

I would not put a bonded plate next to the pressure plate - tha later is not designed to work with a bonded plate - the contact area is too small and I suspect that it would soon cut into the bonded surface on the bonded plate and give you other problems.

The other issue to be very sure of when considering adding a plate is whether, when the clutch is disengaged, that plate can move clear of the chainwheel and/or centre drum and drop.

The spring cups, I think, are about 1 inch long and the A10 type are 1 3/8 inch long.

[Stebbing]

I've just taken my B31 (alternator model) clutch to bits. It has 4 friction plates and 6 metal plates. The previous owner attempted to repair it then just packed them all back in any order. I assume it has a metal plate at the front and back then the four friction plates sandwiched between. Any advice?

[Stebbing]

See my post above.
What do I do with the sixth plate?
Also, where did you get the diagram showing a cross section? Very useful.

[JulianS]

The cross section came from the owners manual.

[idie]

As I said before start at the back with a steel plate then a friction plate. You should finish with a steel plate.