Norton Commando one finger clutch. 

This bike is equal to the reputation the Combats had for unmatched acceleration back in the day, the clutch does not slip, despite being as light as you can see in this video. I make a funnel out of Bluetack, squeeze it around the outer cable, and run EP140 down overnight. But the reason this clutch is so light, (used to be a very heavy clutch), is to do with the stacking of the clutch plates, the diapram shouldnt have to go very far before it flips.