I just bought a 97 blaster from a dealer who had just given it a new top end. My second ride on it turned out to be my last when I was riding WOT in 6th gear and she just locked up. Now, most of you are going to blame the automatic oiler, you're probably right, but let me finish. As it was warming up before this ride, it was smoking like a b!tch so I know it was getting oil. After it had siezed and cooled down, I was able to get it started again, and it still smoked like it was getting sufficient oil. I pulled the piston and there were some pretty deep gouges in a few spots uniformly around the piston, and there was also some streaks of melted aluminum in the cylinder. So it's clear to me the piston overheated and expanded beyond the limit of the cylinder. My question to you is, why?
If the oiler works at idle, is there any reason why it would quit only at high RPM?
If it is decided that the oiler is the culprit, is the blockoff plate really necessary or could I just plug the port in the carb and run the pump dry?
I'd appriciate any help you guys can give.

 

Im not sure but the same sort of thing happend to me but I took off my oil injection and are pre mixing my gas. what happend to me is i was wide open in sixth gear and it just seized, I kicked and kicked but couldent get it to budge. I let it cool down for about 10 min. and kicked it once and fired right up. I drove it home and looked inside to find a few scuffs but nothing to be worried about. if yours had major damage it might have been hard conditions maybe? what where they?

 

I would suspect that the bore was not properly machined to allow the piston to expand. You might take a measurement of the bore and piston and ensure the proper clearance.

 

I agree with ^^ or your to lean and need a bigger main jet.

 

Did the piston look oily? On a failed oil pump the piston will be dry as a bone.