Has anyone had any expirences with sleeving a KXT or KX cylinder with a borable, iron sleeve?? When installing the sleeve, is the cylinder bored to the water cooling passages?? Heres the scenario, I have a 2001 KX500 motor with a borable, iron sleeve installed. This was already installed when I bought the motor. After it running like garbage for awhile and seizing, I took it down. It had a blown head gasket between the fire ring and a water port, I also noticed that the sleeve was shifted or turned a bit and did not match all the ports well. I sent the cylinder to MCR and they reset the sleeve, match ported it, lapped the cylinder to the head and did a complete top end port job and head mod. I ran the motor in 4 races this past year and it just seized again. Jetting was rich and was checked all the time with frequent plug readings. In the shop, I removed the exhaust pipe to have a look at the piston. It had small drops of antifreeze on the exhaust side of the seized piston. I immediately thought that it had ate another head gasket and washed the cylinder wall down again with coolant, but after removing the head the gasket, the seal was perfect!! No apparent issues. How would this coolant be getting into the cylinder?? I can see no apparent cracks. My first thought was that the new port job and head mod had gotten to close to the coolant passages, but I cannot see anything. My other thought is what if the bored cylinder clearance was made to big for the sleeve or oblong. Could coolant leak past the sleeve, down to the crank and then work up to seize the top end?? The coolant was in terrible condition and it was not very old, only a few months. Very yellow with the coolant passages all gumed up with what looked like exhaust goo. Could this sleeve and the cylinder be expanding at different rates and causing these issues?? Any info. would be greatly appreciated. Thanks.


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