Just got my Explorer back from the shop this weekend, got it bored out and steering problems fixed. It runs great! Alot more power, its a blast now, and super quick. But, on Sunday I was being a showoff and pulling wheelies on the alley behind my house and the chain broke and put a hole in the case. It wasn't too big a hole, and I was able to patch it myself. What can I do to prevent this from happening again? Are there chain tensioners available for the Explorer?