Bike: 05rmz250 So I started her up yesterday and was letting her idle. Here in MI it's been real cold so I've been starting it about once a week and just going over everything. Everything was running good. I gave a bit of throttle, may have got a little carried away and gave it too much. Engine came to a halt and the kickstarter wouldn't budge an inch. I'm immediately thinking, I sent a valve through my piston or I broke my crank, seized it up, etc. I started to tear her down, and right when I untensioned the cam chain to take the head off, the kickstarter freed up and the piston moved in the bore along its stroke just fine. I pulled the head, valves look great, piston and bore look great. No gouges or dings in either. I haven't gotten into the bottom end, I will this weekend. One thing I haven't done, which is what I'll do today after work is pull my oil filter and check for metal shavings, although I didn't see any when I drained the oil. Anyone have any idea what could have happened? Engine locked up, then freed. The piston, cylinder, and valve train all look in great shape.