Answer 1: There is a small packet that comes with the Savvy XSS that has a washer with a hex hole in it. This is a changed part for the clutch bell. The screw on the clutch bell must be very tight and have loctite on.

Answer 2: Follow the instructions. Tighten all the way and 1/4 back to MAX 1/2 turns back. You will not be able to test the slipper clutch with your hands, but believe me it does slip. You can see it when you take it apart after a few bashing sessions.

Answer 3 & 4: I think you have your one diff wrong way around. Make sure that when you turn the clutch bell anti-clockwise the wheels spin forward. It could also be that something is wrong inside the rear diff.