After we ran a practice lap or two Saturday, we developed a wicked rattle/popping noise that sounds similar to a chain binding. Took the clutch off and everything seemed fine, chain and guard are clearing fine. Put the clutch back on and it still did it. starts as soon as he gives it a little fuel, then seems to stop when it gets up close to speed. With the kart on the stand and feathering the brake a little, you can clearly see the bail (? inside case with the discs and driver) stops turning intermittently. I'm thinking that when the clutch engages, it should all turn obviously, right?