This winter I spent some time servicing my Model 18. I stripped and rebuilt the gearbox and had the Mag/Dyno checked and refurbished by Gregg Kricorissian in Ottawa.
I stripped the clutch and found the original friction plates were worn well below minimum thickness specifications, so ordered up a new set from the NOC spares team. The quality looks great and I assembled them into the basket, however, with the complete pack installed the last friction plate is proud of the basket and would be unable to engage with the basket splines.
Has anyone else found this problem? I guess I could leave out the last plate, ride the bike until the new friction plates bed in, and then maybe the friction material thickness would have been reduced just enough to allow this last friction plate to be refitted and engage.
I decided to leave the last friction plate out and reassembled everything. The clutch action now seems very light (which is great), but I suspect the lack of the last friction plate may mean the pack will slip under load.
Wondering what the collective wisdom on this would be.... Just try it and see? Or, fit one of the worn friction plates as an interim measure to increase the height of the pack? I would like to try and get ahead of this problem so that when the nice Spring weather arrives I can go riding, rather than starting on another round of troubleshooting.
As always, any opinions and guidance would be greatly appreciated.
Replacement clutch plates.
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As above...
..and keep in mind that Manx clutches often had only 3 plates. Tensioned correctly you should be fine with 4.
J
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Composite clutch plates
Andrew,
In my box of clutch parts I have a couple of clutch plates that have friction material one side and plain steel the other side. I think these may fit the Norton Lightweight machines and are quite handy for making up thickness.
I've not done any research to find out if they're available, but others on the forum may know more about these composite plates.
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Thank you for the help!
Thank you Richard, Jonathan and Philip, that's good advice.
I like the idea of increasing the spring pressure with the judicious use of washers! It makes me feel better that this is a problem that has occurred previously and that dropping a plate is not going to cause any issues.
It's pretty easy to get into the clutch and change things around, so I will let you know how it works out when we finally get a nice Spring day to try the bike out!
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Hi Andrew,
This is a common problem as the original friction plates had the friction pads as inserts in window cut-outs like the chain wheel, and this made them quite thin. The new plates have bonded pads on a solid plate which makes them thicker. Just fit 4 friction plates even though this leaves more room as this is better for clutch dis-engagement. Fit some new spings and see how it performs. You can always pack washers behind the springs to increase their pressure. Make sure the activating arm is adjusted correctly.