Clutch Sprocket Inserts

Hi David,

The Ferodo inserts in both the sprocket wheel and the original fiction plates are designed to be an interference in the holes and when fitting new inserts, may need to be fitted individually into each hole. You should be able to notice the sprocket wheel inserts are thicker than the ones in the friction plates as the plates are thinner. When the inserts are new they should be about 1/16th of an inch proud on each side of the plates and sprocket. When the clutch has been used the inserts become lose in the holes and often fall out when you dismantle the clutch. This is not really a problem when in situ as the spring pressure clamps it all together and the friction plates become semi floating items and are literally just holding the inserts in place.If you have bonded friction plates (these are not original)this obviously does not happen and can lead to clutch drag if the plates distort. Your sprocket wheel inserts should find their own central position when under spring pressure, so no worries, just clean it all up and put it back together. By the way, the 500 Manx had 50 bhp and only 3 friction plates! Regards, Richard.

HI again,

It's possible the serrations have been filed back on the engine plate footrest lugas they get rounded over if the footrest becomes loose and this may have left it short. I quite often remove 1 friction and 1 plain plate from the set, especially if I use bonded plates, as the clutch is packed quite full as standard. This gives more clearance and helps prevent clutchdrag and you can always add spacers on the springs if you need to increase the pressure. I don't know if any of this applies to your bike, but just thought I would add it to the thread.

Hi again David,

The serrated washer sounds a good idea, but it will take a while to make. The comment on the plate removal was just a general suggestion for when bonded plates are used.I am wondering if the gearbox end float is excessive as this should be around20 thou of an inch. If more this might mean the phosphor bronze thrust washeris worn down and allowing the clutch to oscillate and rub against the outer case.

I would be a bit dubious about trying to seal the crankcases with-out removing the engine altogether. I think you could end up making the leak even worse if you loosen the bolts, personally I would check they are all tight enough and live with the leak until you can tackle an engine strip. You might want to check the exact location of the leak as sometimes oil runs down from the timed engine breather hole under the main bearing boss to the bottom of the crankcases.

Regards, Richard.

If the friction insets in the chain ring are flush with the surface, the steel clutch drum will run on the mating plain steel plate. My feeling is that you should centralise the inserts before assembly.

Does your clutch centre have a circlip on the drum? This is provided to limit the outward movement of the plates, and may reduce the need for high lift of the pressure plate. Another factor is the condition of the splines on the plates and basket and drum. If these are worn, there will be clutch drag, and riders will try ever greater clutch lift to try and get a free clutch.

Paul

Previously David Cooper wrote:

Thanks Richard. I'll re-assemble. The clutch did not give me any problems. Apart from the fact that witness marks on the outer case show that the three clutch screws just touch the case when on full lift. And I cannot get the centre nut on together with the footrest unless the cover is pressed very tight.

Hi David,

The timed engine breather hole is located behind the primary chain-case in the main bearing boss of the crankcase directly under the flywheel main-shaft so you will have to get down on your hands and knees to see it. The way this works is that the main-shaft is hollow for part of it's length from the flywheel end and then has an exit hole drilled at 90 degrees so pressure can escape from the crankcases. The timing element is controlled by the corresponding exit hole in the crankcase and the position of the hole in the main-shaft relative to the stroke of the engine.

Hoping I have described this correctly, regards, Richard.