750 stx repeated siezure

[reedjet]

hey guys im working on a 98 kawi stx 750. the engine is running super hot, (melting paint off of head) and I keep siezing the mag piston on the INTAKE side of the piston. at first I thought it was carbs, so I kept pulling them, lowering pop off, opening needles etc. no help. it is pumping water because the pee tube is working perfectly. it does not appear to be a water sieze, because the piston is very hot and carbon is burning onto the combustion chamber. i keep thinking air leak so I yanked the engine back out of the boat today, pressure tested it, and it passed. the motor is bone stock, with .004 piston clearance. Im scratching my head bigtime here. usually when I see seized pistons because of heat, it is on the exhaust side. any help would be greatly appreciated.

[Technical Support]

Re: 750 stx repeated siezure

You could have an issue with sand blocking the passage ways in the exhaust pipe. I have seen this happen and cause the issue you have. Tom SBT tech.