Topic: Clutch Material - Technical Questions for the Old Guys

[RRRToolSolutions]

The young fellas too - if you know the answer.

I have restored dozens of bikes over the last many years and one thing about clutches keeps coming up -

The outer clutch baskets coming out of bikes with their original "cork over resin-core" fiber disc always seen to be perfect. The outer basket's slots aren't damaged, they aren't rough, and the plates slide smoothly in/out as the clutch is pulled and released. These resin-cored plates simply don't chew/damage the slots along the outer basket.

Every basket I've pulled from a bike with aftermarket fibers have scarred, rough, damaged slots. This damage really shows it's ugly head when you're trying to be smooth on the release and engagements. Often times the plates aren't sliding quickly when coming up through the gears, so wear on the dogs, teeth, and drum are accelerated. Bottom line, it's my personal opinion that using fibers with aluminum coring is a small gain in savings, durability - that will soon eat it's way into problems in clutch use and smoothness.

Can some of you guys that remember the change tell me why? It is not that aluminum coring is bad, it's that our basket material was designed for resin-cored fibers. I have one example where the factory used steel-cored fibers, but shaped the spurs into "L" shapes so the spur had twice the normal contact area - something aftermarket fibers don't have the smarts to copy.

Input/opionions, and ideas welcome.

Thanks,
Gordon

[HondaMan]

Gordon:
One thing that's not immediately apparent on the stock STEEL plate/cork setups is the precision with which they are stamped and finished, on Honda's own (or Suzy's own, for that matter) plates. They have edges that will initially bend over to enable max contact edges to engage soon, then the edges wear off and leave a perfectly "matched set" that lasts a long time. If the pack is removed and the outer fingers' positions changed (or the plate order mixed), the process has to start all over again. Typically, I filed the edges of the basket flat when starting a new set, for this reason. Then they don't hang up with the new ones.

Enter the fiber spline types of plates: they are cheaper to make, and wear into the many-finger-contact model quickly. As long as there are enough plates and teeth making contact, they don't warp. If they do warp, they tend to spring back to straight, due to the memory of the fiber laminate. The steel ones, once warped, stay that way. They seldom wear the basket, as they are weaker than the steel.

So, the fiber ones are more forgiving of punishment in the long run, while the steel ones often outlast them.

[bryanj]

OK how about the steel plates with holes that you pushed corks into??? (never found on japs yet)