I've had this bike for about a year now, the previous owner had just put a new piston in the bike prior to my purchase. No more than 25 hours on the top end, but I'm not sure about the bottom end. My friend was riding this bike when it just slowly died. He kicked it over many times without it starting (20 +). When he brought it back to me, I removed the spark plug and attempted to kick it over and check for spark. After 2 or 3 kicks, the kick starter seized. I figured it was the piston, but upon removal of the cylinder, it became obvious that it was something in the lower end. I managed to break the crank free with a ratchet. It took quite a bit of force, at first it rotated with some hesitation but now it rotates smoothly. I will post some pictures if necessary. This is my first engine seizure on the bike, and also the first time I'm attempting to do all the required repair work myself. I'd also like to know what to check for to ensure this doesn't happen again. I've always mixed premium fuel at 32:1 with good oil, my air filter gets changed ever 3 hours. The flywheel shows no signs of a crank seal air leak. I'm thinking the crank bearings just finally wore out naturally. The only two other issues that could have been hard on the engine were running it out of gas (accidentally forgot to open the fuel valve) and there was some 'popping' on closed throttle deceleration because my idle was set high. From what I understand however, this isn't detonation but rather fuel igniting in the pipe. I'd love some advice, and I'm also not sure what parts to buy to rebuild the motor. I was set on the Hot Rod bottom end kit and a Wiseco piston kit. Now I'm not sure about the Hot Rod crank, seems that people have lots of problems. Should I have the cylinder checked out by a mechanic? Opinions on stuff like that would be great, like I said, this is my first serious bike problem!