Motorcycle clutch corks

[olderdan]

1919 AJS dry clutch, 84 round inserts .15.5mm dia and 24x9mm inserts in total, no way to buy these. Rather than make special tooling I have modified standard metric hole punches by grinding to size required. I have used wine bottle corks and can get 4 inserts per cork parted of with a knife blade. I do 32 at a time as I dislike repetition work, once fitted they are ground flat in the lathe both sides with a ragged edge mounted point wheel.

[Isambard]

Back last century, when recorking clutch plates was the norm, to trim the corks, accepted practice was to use an engine exhaust valve that was refaced to a fine edge as the tool in the lathe...
As most used wedge shaped Ferodo inserts originally, the corks, procured from the local pharmacist, were boiled up, to soften, then pushed sideways into the recesses, allowed to cool, then trimmed. Pharmacist corks were preferred over those from the ironmonger, as they were very high quality, no flaws.

[nova_robotics]

I had no idea cork was used in clutches. I know the Ford Model T used leather bands as friction material in their transmissions. But cork is a new one. That's great. Well done.

[olderdan]

Most brit bikes up to the 50s used cork inserts usually oil bathed until bonded plates became the norm. Villiers engines all used cork and I have done hand cut inserts for those although they are still available ready made.

[DIYer]

Thanks olderdan! We've added your Clutch Corks to our Motorcycle category,
as well as to your builder page: olderdan's Homemade Tools. Your receipt:

Clutch Corks by olderdan

tags: clutch