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99 mxz burning down the pto side piston.

F
Nov 27, 2007
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Hey guys have a buddy thats having major issues with a 500 mxz. I helped him on the rebuild 2 burn downs ago, we replaced all the gaskets, pto seal, mag seal, cleaned the carbs, ensured the jetting was correct and the carbs on the right sides.

this last time he had about 600 miles on it wasnt riding it hard till the day he burned down, he was WOT with his son on the machine when it blew. He said this last melt down was in between the exhaust ports........
he is getting really frustrated with this machine. having burned 4 pistons with it. (same side)

any Ideas why this is happening? or solutions?.
 

joshkoltes

Well-known member
Lifetime Membership
Dec 16, 2007
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ranchester, wy - nashua, mn
bearing

did you just replace the seals in the crank and not the bearings? they are expensive but so is more pistons. clean the bearings with some kind of stuff and listen for noise. if they roll quietly and freely then i dont know i guess iv seen a broke rod crack the case and nobody noticed causing air leak and burn down?
 
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skidoorulz

Well-known member
Nov 21, 2007
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Billings Montana
Cracked carb boot? Are both carbs jetted the same? They aren't supposed to be. The PTO side should have a richer jet in it
 
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