yeah no prob but i never let my lt250 warm up well sometimes lol and never blow it up..but anythings possible

 

It was warmed up for a good 5 minutes before I even went for the ride. Before it was "opened up" it had been running for about 15 minutes.

 

Does anyone have any more in-depth info about this? I was just told that there is a cut through the rings and into the front of the piston on the exhaust side again. Everything else is fine.

 

not to sound like an *** but is the piston in right. your ring gaps must line up to certain areas of the cylinder wall. if the piston is rotated 180* these will not line up. I only know this becuase I did it once. getting in a hurry cost me 175.00

 

This piston and rings were installed the correct way. Everything went back together real smooth. It actually ran great for about 3 hours and then when I started to really run it, it tore up the front of the piston.


It just seems like something strange is going on since both times it destroyed the front of the piston. There is no evidence of being too lean either. Looks like someone took a file to the front of the piston.

 

sounds like bores to tight or it wasnt chanfered or how ever u spell it properly .since u narrowed the rest pretty much out with the not running to lean aspect.

 

maybe there is a lip on your exust port.

 

did you drill relief holes in front of piston where exhaust bridge runs? or it was running hot for some reason like waterpump aint pumping like it should ,maybe fins broke or something on water pump.?etc. if it did it 2 times that could be the problem.

 

The piston had 2 small holes on the exhaust side beneath the rings. I assume these were the relief holes?

As the cylinders are bored can you start to have clearance issues with the exhaust power valve? Could the exhaust valve when fully opened be sticking out just enough into the cylinder to hit the piston at high rpms?

When I first got this thing back from being rebuilt the power valve was not functioning right. Once I took it all apart and reassembled according to the book it worked great. Instead of a real "jerky" powerband and 4th thru 6th gear being dead the thing ran the way it should have.

Then as soon as I ran it hard the first time and really used the higher gears this powervalve would be opening and fully functional for the first time. Next thing ya know it's dead and the front of the piston is destroyed.

 

Take out the powervalve and see how it looks. It would be scarred up similar to the piston.