A month or so ago, I went for a ride up Bristol Mountian with a buddy on my YZ250. It was about 45-50 degrees out, clear day after two weeks of non-stop rain that caused some serious flooding in areas. Good ride, until on the return voyage, my bike make a loud noise, and then screamed in agnony with a “whapwhapwhapwhapwhap”while smoke plumed out the front. Nuts. Seized.
I’ve heard of two-strokes seizing before. I had originally thought that the source of the seizure was from too much mud and water getting in through the faulty exhaust port seal. I discovered later that it was simply because I hadnt changed the jetting on the carb for the colder air, the mixture leaned and heated up the cylinder too much. Finding that I only had a half a cup of coolant left in the radiator solidified this explanation. (Yes, it was full when I left for the ride.)
So, I figured I’d free the piston from the cylinder, get the cylinder bored .2mm over (just to be sure) and slap a .2mm over piston in. Throw it all together, give it a kick, and wheelie off into further dirt adventures. As the picture above proves, I was wrong, wrong, wrong. It got so hot, and the piston (assuming from 1988) was so old, beaten and worn, that the skirt simply started to disentegrate, fragment and wap around from the heat. One of the peices must have lodged itself just right against the cylinder, that it took a few decent chunks out of the liner, and marred the shit out of the cylinder. If that wasn’t enough, I fished these peices out of the middle of the crank.
I’m at a cross-roads. I bought the bike fairly cheaply, and heavily used. Before this, it needed some work done to the swingarm pivot points, and the suspension dog-bones. Now I’m looking at a new cylinder, piston, and a case-split to remove all the piston fragments, and ensure that the main bearings arn’t destroyed. I’ve had a whole summer of memories on the little green bastard. But is it worth breaking my back all winter-long to get running again? I havn’t been this confused since I got my first boner.
November 27th, 2005 at 2:36 am
Man, that SUCKS! I have never seen one wiped out that bad. I don’t know how you even got it apart. Now I am scared for mine, I hate it when my toys are broke.
I just thought it meant I had to pee…but I couldn’t.
November 27th, 2005 at 9:36 pm
Just because the piston was whacked doesn’t mean the cylinder is done. Give he two mm a try. The build up of aluminum transferred to the cylinder should clean off and the oversized piston should fit fine. I’ll bet the piston was way worn and slapping around the cylinder before you got it. Might be an interesting lathe project:razz: