Wow!!

So i took apart my snowmobile head last night because the last time i rode it it wouldent go past 40mph no matter what...i knew something was wrong but i had to ride it 10 miles back home and i knew if i shut it off it wouldent restart.

Now it being july i figured i should get it fixed so ill be ready for when theres snow...but i dident expcect this.

IMG_0188-2.jpg

IMG_0187-1.jpg

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:busted::thumbsup: :thumbsup:

looks like the surface of the moon.

I had one piston on my sled get a hole and have a chunck missing, took me a few hours and the sled was ready to go.

Damn dude, that sucks, what do you think happend?

Im not really sure what happened....but im thinking a gasket blew and allowed to much air in making that piston burn way to hot so it melted. :thumbsup:

Im hoping my crankcase isnt gone from all the metel shards that have probably circulated through since i had to ride it 10 miles like that.

GAWD! That's a pain.

I hope your bottom end looks all right:thumbsup:

that sucks:crazy:

it might be the bottom end thats done cause if somethin shredded in the bottom end then it would go up to the top and shred the top surface of your piston. Im not sure but thats what happened to my old 80 but the piston still wasnt that bad, just a couple scratches even tho there was freeplay with the rod going side to side.:thumbsup:

That dont look to good

I really dont even wanna look at the bottom end since the top was this bad but im gonna have to :thumbsup:

If theres alot of damage to the bottom i might just pull the whole engine and drop a 670 in there cus its only a 500 now and im pretty sure the chasis are the same on that year MXZ's.

:thumbsup:

^ way to turn a bad situation into a semi-ok one :thumbsup:

^^ haha thanks...it still blows tho

Does anyone have an idea what mighta caused this...ive never had a piston fried this bad

HawkGT would know. hes very knowledgeable

Clutch side? Blow a belt recently? Crank seal on that side. That happened to me on 2 different sleds over the years - crap from the blown belt takes out the seal, runs lean until it's too late.

Clutch side? Blow a belt recently? Crank seal on that side. That happened to me on 2 different sleds over the years - crap from the blown belt takes out the seal, runs lean until it's too late.

yea it is the clutch side..but the belt was ok...i actually just changed it before it happened.

It seems like when i was riding it beofore it happened it was faster then its ever been...like it would take off alot quicker and hit alot harder then it did before...then that happened so i dont know :thumbsup:

You got bad gas with too much ethanol or methanol in it making it too lean which than makes it run hot and burns/melts the piston..

It would have happend to both sides if it were bad gas. Something had to have broken off in there ...what did the skirt look like? I hAd one break on me and it chewed it up. I could see it getting hot but once the "seal" is broken or melted there wouldnt be anymore "kaboom" right? I think it was just 10 miles of parts and junks beating that piston. Do the 670 you wont regret it. :thumbsup:

:thumbsup: wow..........that looks real bad

good luck fixing her:thumbsup:

It would have happend to both sides if it were bad gas. Something had to have broken off in there ...what did the skirt look like? I hAd one break on me and it chewed it up. I could see it getting hot but once the "seal" is broken or melted there wouldnt be anymore "kaboom" right? I think it was just 10 miles of parts and junks beating that piston. Do the 670 you wont regret it. :thumbsup:

The skirt on it was actually wasn that bad...it wasnt broken or anything. but as you can see from the picture lit looks like there is seizure marks in the piston and there is also some on the cylinder.

If i have it fixed, both cylinders will have to be re-bored?

I would think so, so they are equal:excuseme:

It would have happend to both sides if it were bad gas. Something had to have broken off in there ..

NOt necessarily or do you have one carb for two cylinders? One carb might have been slightly off and then the bad gas was above the tolerances of the piston.

that piston is destroyed

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