Word of advice, don't buy a Black Magic clutch kit under any circumstances. I had one on my ZR 600 as well as the pipes, etc. No matter how I adjusted it it would always engage with a real sharp jolt. Wrecked the keyway on my jackshaft because of this and is probably a big contributer to my track coming apart. Also I beefed up my new jackshaft with a wider, thicker key so I would almost guess the crank will be the next part to not handle the load.
Hearthrob=Heartburn!