What happened to my piston?? (pics)

[rookie23]

sled died at the end of the day...in and out of throttle..45-55...pulled her down and this is what i found...4 corner...cold seize? thermostat? any other ideas?
edit: was mag. side...top of piston looked pretty clean...like maybe too much gas?
more pics to come

 

[hymark860]

How hot did it get on the trail out?

 

[rookie23]

outside temp was bout 20 degrees. had good amount of soft snow on the trail....and was off trail every chance i had in the pow....temp light never came on....which i guess doesnt mean anything....but wasnt to the point where i thought i wasnt gettin enough snow??

 

[whitefish]

Looks like some deto on the top edge. Hard to tell from the pics. Post up some macro shots of the top edge and underside of the ring grooves.

Who's kit are you running?

 

[milehighassassin]

I am not 100% sure but there really is no such thing as too much gas/fuel, right?

I didn't think you could do damage from running rich.

What do your carb boots and reed boots look like?

 

[rookie23]

will get some more pics up soon...thanks for the input so far guys...its an RKT kit.....

 

[theultrarider]

Head gasket leak....causing some det and washing the piston tops and the oil off the cylinder walls.

 

[whitefish]

Head gasket leak....causing some det and washing the piston tops and the oil off the cylinder walls.

Unlikely. If that was the case it usually fails right off the bat.

 

[Idaho Slim]

RKT piston - 4 corner seize - hmmmmmm ..............................

 

[Trashy]

RKT piston - 4 corner seize - hmmmmmm ..............................

What are ya thinkin' Slim???

 

[rookie23]

was waitin for u to chime in slim!!!
so what caused the 4 corner??
carb boots started to delam. on one corner...bout a quarter inch long...that enought to wreak havoc??

 

[skibreeze]

was waitin for u to chime in slim!!!
so what caused the 4 corner??
carb boots started to delam. on one corner...bout a quarter inch long...that enought to wreak havoc??

The delam can only be a culprit if there is a hole in it. Can't see the tops of the piston well, but it looks lean from what I can see.

 

[Seeder]

Too tight possibly or I have seen this happen from t-stat stick longer than it should and allow the cylinder to heat up too much, but not overheat and thus allow the coolant to cool more than normal and when that t-stat finally post with a hotter than normal cylinder and a cooler than normal coolant you get a quick cold seize like that.

Varify tolerances and rebuild with new t-stat or delete it.

-Frog

 

[theUltamateTBM]

every doo I have seen down this year looks like a 4 corner some of the guys I work with seem to think they are a tight tolerence in the first place but have more than plenty lubrication so when it gets hot it is to late also I no from expirence that the doos will overheat if you let them warm up for too long and I do work in a shop

 

[rookie23]

few more pics added...

 

[triple7]

Did you verify that it is getting oil to both this side?? Just an idea

 

[MARCUSO]

RKT piston - 4 corner seize - hmmmmmm ..............................

Ya, kinda like Alberta Boy's HMMMMM is right!

 

[Red-eye]

lack of oil is the cause, better check it out.

 

[m8magicandmystery]

one piston top has no wash at all,,,,

 

[madmax]

What was your set up, what motor and alt.