The attached photo's are of the piston I pulled out of my friends 1992 Polaris RXL 650. Before I go and replace the cylinder and piston I wanted to ask you guys if there might be an underlying problem that may have caused this failure? Note the dimple in the center of the piston...it looks like the plug smashed the piston head....not the case, the spark plug is fine and the connecting rod is intact.
Any suggestions are welcome
Thanks in advance
Jedrow
Any suggestions are welcome
Thanks in advance
Jedrow
Attachments
2003VIPERER
New member
I Had The Same Problem In A 2000 Polaris Xc600 Except For The Fact That A Hole Was Burned Right Through The Piston. Found Out To Be A Lean Condition. Clogged Jet In The Carb.
Is the dimple on the exhaust or intake side of the piston?
Looks like it definitely got very hot adn almost burned through. As already suggested the carb may have been plugged and caused a lean condition which burns up pistons. You may want to look for other areas that can lead to lean conditions like failed crank seals, carb boots etc.
Mills
Looks like it definitely got very hot adn almost burned through. As already suggested the carb may have been plugged and caused a lean condition which burns up pistons. You may want to look for other areas that can lead to lean conditions like failed crank seals, carb boots etc.
Mills
SpartaSXr
Member
lean burndown
JohnnyQuest
Member
it's a lean burn down, either caused from a plugged jet, TOO Lean of jetting, or TOO Lean of a needle setting
montynormand
Member
WAY LEAN... Ritchen her up. But is it lean in Full open or Mid range?
Weatherbyman
Member
It's detonation
Jed Ashby said:
Forgot to mention...its a fuel injected snowmachine. This burndown happened at WOT. There is a suspected water leak in the head. Looks like a previous owner tried to remove an old gasket with a file and damaged the sealing surface on the head. Question is....would a small coolant leak into this cylinder cause this failure? Why? Or am I barking up the wrong tree.
On the other hand...was the coolant leak into the cylinder caused by overheating by the lean condition?
Thanks again