Heavy AMC clutch

[shaunstaples]

Is there anything similar to the Norman Hyde 7 plate clutch for triumphs? I fitted one to my Bonneville and it transformed it. The friction plates have the centre diameter increased to increase the torque it will transmit. The friction plates are thinner so an extra plain and friction plate can fit in the basket. In the kit is 7 friction 1 plain and lighter springs ( because it will transmit more torque the lighter springs are enough ) It transforms things and stays set up as the pushrod etc. is under less pressure.

[Anders Welle]

Many thanks for the many helpful comments. Looking through the factory spares lists from 1958 on, I now find that the standard spring 040385 is listed for both 4 plate and 5 plate clutches except from 1962 on when the heavier spring 040358 appears for CSR only, as well as different studs 043441 and pressure plate 043362. The spares scheme list the heavy spring for all 5-plate clutches 1960-on which then seems incorrect. I purchased both types and my installed springs match the standard spring.
I find in the factory lists that both 4 plate and 5 plate clutch types share springs, adjuster nuts, spring cups, studs and pressure plates. (I am focusing on 650 twins here, singles can have different pressure plates corresponding to the number of friction plates). My conclusion is that I have indeed the correct clutch parts for my model. The only remaining action will be spring adjustment. I have assumed the adjuster nuts needs to be flush with the studs. I will try slackening the springs as suggested by several of you until I have acceptable lever force - but no slip. Will there be a problem with the adjuster nuts protruding slightly from the cups? Can the nuts work loose? I will also install new friction discs. Next year the Ajay must be in top shape, as we celebrate 50 years together.

[Groily]

AMC clutch.jpg

I have assumed the adjuster nuts needs to be flush with the studs. I will try slackening the springs as suggested by several of you until I have acceptable lever force - but no slip. Will there be a problem with the adjuster nuts protruding slightly from the cups? Can the nuts work loose? I will also install new friction discs. Next year the Ajay must be in top shape, as we celebrate 50 years together.

I don't think they do (need to be flush with the studs). This may depend on the exact length of the studs, of course, but as far as I know the ones I have are correct . . .
The pic here shows my 650 clutch when I opened things up the other day to check it and the condition of the primary chain & c/shaft sprocket after 1000 miles seriously hard riding round Spain.

You can see that the studs aren't close to flush. I did give them a turn extra while I was in there just for luck and to compensate for any wear on the plates, but she'd run like that for several years and many thousands of km, nothing had obviously backed off and the unit had retained correct adjustment and operation.
You might spot that one of the cup nuts doesn't match the other 2 exactly, as it has a slightly thicker shoulder by the look of it - but that has no effect at all.

If I screw the nuts down flush, the unit is no grippier, but is much heavier (and hard on the cable nipples as well).

My own rule of thumb is to do 'em up - with the pushrod adjuster backed off enough to ensure full compression of the stack - until there is no slippage on the kickstart (this one has 8.5:1 pistons in it) and then give them another half to one turn, using my eyes (and sometimes a 'clock') to tweak for an even lift of the pressure plate. Then I do the fine adjustment of the pushrod, with half an eye on the lever at the kickstart end to be sure it isn't operating at a silly angle owing to wear anywhere and is in correct alignment. Then, sometimes (if I can be bothered to hook up the brake etc!), I run up and down my lane with the outer primary case off to be sure it isn't slipping or dragging . . .

[Duncan]

Will there be a problem with the adjuster nuts protruding slightly from the cups? Can the nuts work loose?

The later AMC clutch thimbles have a register that locates in a corresponding notch in the pressure plate to prevent it rotating, additionally there is a punched register in the bottom of the thimble and the underside of the adjuster screw to prevent rotation within the nut/spring/thimble assembly.

[Joker_Bones]

As Duncas says...
You may find the dimple on the underside of the adjuster nut flange has worn flat.

IMG_20231109_190607.jpg

If you find something to support the flange and cut a slot in it you can re-punch the dimple. I used a T slot clamp nut.

IMG_20231109_190925.jpg

Go steady though, they are soft steel nuts... first time I was over enthusiastic with the hammer and easily punched a chunk right out of the flange.

[MalcW]

The adjusters on my 650 clutch are nowhere near flush with the studs, and I have no problem with clutch slip. As a start point I normally do them up until the pressure plate is releasing evenly and I can kick the motor over with no slip, plus 1 turn, As has been said, make sure the cable and actuator are aligned on the kickstart side, you have a smooth cable run, the cable itself slides freely. I always slacken the cable right off, take up the free play at the clutch centre adjuster end, then back it off about 1/2 a turn and finally fine tune the cable adjustment.

Malc

[Anders Welle]

Thank you all for good advice. I find that unscrewing the adjuster nuts 3-4 turns from flush with studs gives me an acceptable barely-one finger lever.
I Will check for slip and adjust accordingly in spring. As for the adjuster nuts my dimples are worn away, so they Will be restored. With New plates I anticipate a sweet clutch!