One clutch thrust washer or two?

[Martin K]

Drags picture of the FH clutch shows one thrust washer - but they indicate 2 are needed per clutch. So this might be a pointless question filed under ‘just making sure’ but here goes….

With only one thrust washer fitted, the rear primary cog (big one that sits behind the clutch) just catches slightly as it turns (against the rear primary cas). Presumably add a second washer, and clearance is restored?

And I guess it’s not thick enough to push things (like cogs) out of alignment?

And finally, once the split point is fitted to the crank shock absorber, do I unwind the nut/spring combo back out until it pushes against the split point and can’t go further so it’s ‘set’

Advice welcome, thanks chaps.

[pete.collings]

There should be two thrust washers, originally the one behing the chainwheel centre was plain, and the one in front had a ridge that located with the chainwheel centre ridges, but as these were no longer available, two plain ones could be used instead.
On my Huntmaster, I screwed the spring retained up hard against the end of the crank, and then fabricated a short sleeve to fit over the threaded portion of the crank, filing two grooves that allowed the split pin to be just tapped into place with no frre play, and then bent over, with no movement possible for the spring retained to unwind, as I had previously encountered, and maintain spring compression. If wound back, the movement of the spring retained could sheer off the split pin, as it is soft metal.

[Mick D]

Hi

Like Pete, I fabricated a spacer to take up the slack between the split pin and the nut, I don't think there's any necessity to groove it to accept the pin .

Shock Absorber Spacer.png (197.01 KiB) Viewed 366 times

I also had slight contact between the clutch basket and inner primary during assembly. A bit of investigation showed that the inner primary is easily flexed and the fitting of the outer primary, battery carrier, bottom stud etc. eased it into it's correct location and negated the contact.

I'm pretty sure I used the set up as per the Drags drawing with a thrust washer either side of the needle roller/basket, ie. 2 off pn 3394-36.

I also made a spacer to suit the fwd FERC mount which affects the alignment of the inner PCC:

PCC - FERC Tab.png (278.05 KiB) Viewed 357 times

Fwd FERC Spacer.png (253.67 KiB) Viewed 357 times

Regards Mick

[Martin K]

Thanks chaps - sound advice.

A couple of further asks please:

1) if all the movement is taken out of the spring (ie winding it all the way to the end stop) doesn’t that negate the whole point of it - to help buffer road shock coming back through the final and primary drive from thumping the crank? A bit of movement needed to help soften that?

2) I like the idea of a washer/spacer to help limit the shearing pressure on the split pin. Is that something you fabricated yourselves? (I haven’t got the metalwork rig to do that - just wondering if it is a ‘part’)

Thanks

[pete.collings]

Even with the spring retainer screwed in fully, there should be enough movement in the spring to buffer the transmission shocks, in fact having the spring preloaded sufficiently could minimize jerking, assuming the spring is of the correct length and not weakened with age. I have experienced a rattling noise when the spring retainer had unwound, allowing the sprocket cam to ride over, and lessening/removing any drive to the chainwheel.
I had fabricated a splitpin spacer from a bit of tube the right ID size, just hacksawing it overlength and then filing it to a good fit. I prefer a couple of notches to prevent the spacer rotating, that that may be a belt and braces approach to the problem.
One other point of possible use, I always found that a Huntmaster wore the primary chain unevenly (don't know why), so if adjusting chain tension, always use the tightest point of the run to set running clearance. If not, there is a risk of the loosest point of the chain wearing away the primary chaincase screw mounts.

[Martin K]

Great help thanks Pete.