Putting a 67 T120 back together after 2nd try indexing the gearbox/shifter. Fitting the 20 rollers into the basket and hub, using my sticky grease and a stick magnet. I've always enjoyed this little ritual. Then I remembered: didn't John H say we're not supposed to use grease? Then I wondered why not? All done now, but this sort of mechanical esoterica always interests me.
Whatever you put on the rollers will go into the primary oil. On early separate primary/motor oil you will be putting some grease on your clutch plates. On later breathe through primary engines the grease will also be going through the motor. Granted, thinned down. Wheel grease has fibers in it which you do not want in the shell bearings.
[quote]Then I remembered: didn't John H say we're not supposed to use grease?/quote]
While I see no reason to use grease when offering the clutch rollers to hold them in place, or for later lubrication, I cannot remember saying don't use grease. The tension from the primary chain holds rollers in place as the next one is offered. Offer a roller. Then slide it to the back where the chain tension will hold it in place. Then do the same as you offer the next roller until all 20 are in place. Some lubrication from the same oil you will later use in the primary is certainly appropriate.
johns dry method probably works if you have done this enough times that you can do it with your eyes closed . but if youre re-building a clutch in place , only on the odd occasion , like when you absolutely have to ... holding the basket and chain in on hand , placing one roller at a time with your second hand ... and hoping it stays in place while Wrangling up the next roller . is like that circus act juggling plates on the Ed Sullivan show ...( this childhood memory still haunts me ) until enough rollers are in place one dropped roller spoils the party gravity isn't your friend here ... but a little grease is .
When I ran a standard clutch setup I would place the clutch hub flat, basket on then put the rollers in from there and push the Cush drive on after. It was sufficient for keeping it all together. But your relying on blind faith that the hub goes on the shaft squarely and not off set by the key, with the basket in place the visual check is restricted.
Every time I try to assemble the whole thing and slide it on the shaft I hear that faint tink in the bottom of the case which tells me that one roller has just freed itself. Probably why I've taken apart so many which only had 19 rollers in there. I'd rather do it as JH describes, the only difficult one is the last roller.
I didn’t do for many years. The taper on the main shaft is what’s doing the work, the key does very little.
If you were running a spline then, ok the spline would wear if the nut wasn’t tight but it would still propel motion. If the nut isn’t tight on a taper then that key is just going to sheer. It’s doing very little in respect for keeping the mainshaft turning.
ive sheared keys when the nut wasnt tight. what i do is paint the end of the key bright yellow and then run a tracer line down to the end of the shaft. when i put the clutch on i can see the end of the key using a little flashlight
i do the same on camshaft pinion keys
every day you do not take a chance is a day of your life that you will never get back.
Nod nod— you are correct,Kevin! The nut obviously needs to be tight but the torque is transmitted by the taper. Arguably you reduce the torque transmitting capabilities by having the key way there. You should only use a key way if you want to fix the two parts together in a particular place. A good example is to fix the timing in a flywheel magneto. But for a clutch of this design— no! Leave out the key but lap the clutch center and the main shaft together using fine valve grinding paste. Make sure the grinding paste is thoroughly cleaned off afterwards. Make sure that the clutch nut is really tight and away you go. Just my two cents worth of course.
If both the gearboxmainshaft and the clutch center are new then I would trial fit and if snug then I would not lap the surfaces. However at least one of those components is probably 50 or more years old and has probably suffered at the hands of previous “experts”. For example the main shaft key way is often less than pristine with people putting in and taking out keys. So I always do a light lapping- to get a good uniform dark grey over the whole taper on both components. Just my way of doing things.
The fit of the clutch hub on the main shaft of my race Triumph is not the best. Tighten to 60 ft lbs and then back off the nut, the hub comes off easily with the slightest tightening of the puller..The hub is genuine NOS Triumph....it has never caused a problem for land speed racing..
79 T140D, 96 900M Ducati 81 Ducati Pantah 500 ..On a bike you can out run the demons..