I had same problem until I put spacers (washers) on the handle bar mounting bolt to snug it to the frame. I could see it needed this because there was play up and down along the mount. Now, no more rattle, shimmy, or popping.
Instead of a flap wheel, I used a dremel sanding drum bit to open up the bore on the clutch just a smidge. Finally got this thing on the stock engine.
I think I get about 10% more torque on the low-end during take-off with the new clutch. 11 teeth instead of 12. Also higher RPM engagement...
Just bought a dremel flap wheel, but it's too big to fit in the 5/8" shaft for this clutch. Will keep looking.
Sucks a big one that I may end up buying $30 worth of hardware to get a $24 clutch on the bike.
I sanded off the bore on the clutch, and still doesn't fit. lightly tapped it onto shaft with rubber mallet, and it goes on 1/64" at best. Feels like a lot of metal will have to be ground out of the clutch shaft to make this thing fit.
Tried it on a 2nd stock engine shaft, and same...
I just got a Max Torque clutch (5/8") for the stock DB engine. The stock clutch slides nicely off the crankshaft, but the new clutch won't go on. Even with key removed from clutch, no go. Caliper shows shaft is 5/8" and clutch ID is 5/8".
I tried sanding the crankshaft down, but still no...