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Discussion Starter · #1 ·
Burned my sled down couple weeks ago; rebuilt engine with "rebuilt" steel sleeved cylinder that appeared well done, i.e., ports matched and tapered well. Used new Sports Parts Inc. piston and ring. Was riding in a lot of snow dust. Rebuilt engine had about 130 miles on it. After abouit an hour of riding, engine quit as if it had burned down again. Crank was locked, broke it loose, and able to run it a little longer (trykg to return)

Tore it down, and found a very broken, but not burned piston. The front and rear skirts are pretty well gone. Picture attached.

The top of the piston has a little errosion at the front. I believe this resulted from all the broken skirt debris that was trapped on top of the piston, and it getting smashed between the exhaust port top edge, and also the head squish area. There is absolutely no evidence of heat of melting of the pistion top surface. Picture Attached

Any ideas, I am baffled.
Top2.JPG
 

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ITs WINTER!
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Cylinder was out of spec, or the piston was...

Made a few of them myself!


 

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Discussion Starter · #6 ·
sled_to_the_max said:
Hmmm I have them 907 miles and no complaints.Are you sure it didn't over heat and a crank bearing went?
[snapback]710938[/snapback]​
Nope, it did not overheat, and the crank bearings are fine.
 

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HarveyEdson said:
HarveyEdson said:
06MXZXRenegade800 said:
Cylinder was out of spec, or the piston was...

Made a few of them myself!



[snapback]710964[/snapback]​
Only possibility I can think of, hope you're right.

tt
[snapback]711414[/snapback]​
ttt
[snapback]713095[/snapback]​
Did you guy who installed the sleeve ask for the piston with it? It would be needed to set the proper clearence. You definetley had way to much clearence to break the skirt like that.
 

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Discussion Starter · #10 ·
sre said:
HarveyEdson said:
HarveyEdson said:
06MXZXRenegade800 said:
Cylinder was out of spec, or the piston was...

Made a few of them myself!



[snapback]710964[/snapback]​
Only possibility I can think of, hope you're right.

tt
[snapback]711414[/snapback]​
ttt
[snapback]713095[/snapback]​
Did you guy who installed the sleeve ask for the piston with it? It would be needed to set the proper clearence. You definetley had way to much clearence to break the skirt like that.
[snapback]713291[/snapback]​
The guy who sold me the sleeved jug said he bored and honed 5 1/2 thousands clearance to hte piston, BUT I DID NOT MEASURE IT. I probably should have
 
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