I just recently purchased a 110 gio hummer,I've been having an issue with the chain continously popping off.I've had to adjust and readjust so many times that i have the adjusting bolt stripped out.The rear swing arm bushing seems to have alot of play in it.I've tried jamming washers in the swing arm but they keep coming loose.Its very frustrating because its a neet little rig and my 7 year old son loves it,but he cant go 5 minutes without the chain coming off.Can anyone help?