that video was with the original clutch and pulley. with starter arms removed and rivets added to shorten the clutch leaves so as to bite/stall higher. the engine has low rev porting for rideability. all i want is 6500- 7000 bite/stall point.
i did modify a clutch like yours with springs on the leaves but they just wear out in no time with all that spinning.
i can add more preload to my contra spring cos i made it adjustable so will try it on max preload but it looks like i need a launch lever and a stronger spring.
does the business end of the lever contact the engine or the last coil or two of the spring?