Rocho type 5 Plate clutch

[gazza]

Got a Rocho style clutch (actually built by Tarmac Tickler) lambretta 46t crown wheel with Aprilla RS125 basket riveted to it with Aprilla plates and steels. I was experiencing clutch drag so adjusted a couple of turns and all seemed ok took it down to put on Dyno and whilst on the Dyno the clutch appeared to be slipping at speed, so readjusted then as the clutched was pulled in to reduce speed it started to rev high with clutch out. when it eventually stopped it appeared the clutch cable may have snapped but on closer inspection the clutch arm seemed really loose (no resistance from the clutch springs) after stripping down I found the clutch nipple ,Li type, had melted/fused to both the pressure plate and the clutch arm cam. Has anyone else experienced this? Do they need to be set up with a little drag? And what type of oil should be used? I did have standard ST90 in it
Thanks in advance
Gazza

[Digger]

I've had the issue with a non Rocho clutch with the nipple fusing to the clutch lever.

It was because the nipple hadn't been case hardened - I do them myself now before fitting.

[gazza]

Got a Spanish one now when u case harden it do u quench it in oil or water ? And would still be interested if any one else uses this type of clutch what oil they use in the side casing
Cheers

[Digger]

Gazza

Oil - water is no use.

From the Wiki but essentially as I remember it from school metalwork and my apprentice days.

Steel is introduced to a carbon rich environment and elevated temperatures for a certain amount of time, and then quenched so that the carbon is locked in the structure; one of the simpler procedures is repeatedly to heat a part with an acetylene torch set with a fuel-rich flame and quench it in a carbon-rich fluid such as oil.

I use a blow torch to heat them to cherry red then quench in gearbox oil - repeat a couple of times.