Blown Piston diagnosis help... Not spun ring like i thought....

[Summit800_Andy]

Heres a Pic of the MAG side Piston. And the Damage is on the Exhaust side.
And in the 2nd Pic you can see the damaged cylinder wall, as well as a crack in the wall.
What could be the cause?

 

[moto5151]

Looks like it ran dry for a bit. Did it run out of fuel? Looks like heat crack, and scoring.

 

[Summit800_Andy]

Nope didnt run out of fule. This was after a normal length warm up in the parking lot, and about 7-8 KM down the trail and she died.

 

[Summit800_Andy]

All though after it died, i got it fired back up for a bit and ran another few KM before she died and wouldnt get going again. Maybe this added to it?

 

[tex78]

Do ya have the updated rave guillotines in it. Might have cought the piston.

Looks like its in the cylinder farther than it should.

That's not as bad as mine but the top of my piston was mashed up. But then I rode it back 10 on 1.5 cylinders.






sent from my htc

 

[tukernater]

First ride of the year? did you clean your carbs or could even have been old gas.

 

[Summit800_Andy]

Second ride of the year. But Im new to sledding as of last spring and did a half ass summarize... Didnt fog the carbs. Could that be all it took? I did a good 2/3 of a take the first day out though..

 

[Summit800_Andy]

And any tips on getting out a stubborn wrist pin. Other on came out super easy, but this one wont budge!

 

[DRD]

What did the plug etc. look like? Don't see any wash on the piston.

 

[Summit800_Andy]

Plug was black and had some bad carbon build up.

 

[slededjr]

Looks like excessive heat for sure. Ran a little lean maybe from gunk in carbs, old bad gas, mag crank seal leaking a bit causing lean condition. As far as wrist pin, I'm assuming you don't have pin puller, if you have a vice, use different size sockets or pipe and push it out that way. I've had one I actually had to cut the piston off of the pin, then the pin should slide out for you.

 

[moto5151]

Make a pin puller with a piece of threaded rod, and a few nuts.
I never fogged my carbs or summerized my sled. Started it in the fall, topped it off with new fuel and went....

 

[Jason]

Exact same scenario happened to my sons. Determined that it warmed up a little to long once we offloaded and then headed up the groomed trail with not enough cooling. Excessive heat seize the piston then when it cooled it started again then seized again. Almost seems piston expanded faster that the cylinder if that makes any sense.