I'm going to check out a sporty. It apparently has a broken rear sprocket, chain, and guard. Owner was revving engine in what he thought was neutral, but was actually between gears, it slipped into gear, and the chain and rear sprocket and possibly hub broke. What other damage should I be on the look out for when checking this bike out? Seems like it would take a lot of torque to shear a rear sprocket and hub. Thanks for the help.