Anyone have any tips on adjusting the slipper pad/clutch on the spur gear? My son's is installed per the directions in the BTD kit, but offers no slip whatsoever....so it seems too tight. He's stripped out that spur gear in a couple of chunks. No doubt, from the big jumps he does. Seems like if the slipper was a little looser it would keep the drivetrain a little safer, but don't wanna go too loose either. Thanks.