Bought a new chain for my 1988 Suzuki GSX1100F. The PO put a 530 kit on it to change it from a 535. I checked the sprockets and they were fine, for I used a chain breaker to trim the new chain and used the master link to fasten the new chain on. I did not get an O ring chain, because it's an old bike and I am cheap. I have put about 500 km on the new chain. Yesterday, the chain broke at low speed at the master link. The chain was a bit too hot to touch sitting on the ground. I had forgotten to put one bolt back in the plastic chain guard and it was rubbing the chain. What happened? Bad Chain? Friction from the plastic rubbing heated the chain causing a failure? Improper installation of the master link? I have never done that before, but followed the instructions precisely. I had the rear tire changed the day before the failure. Did the shop somehow screw something up? Is it safe to put a new chain on?