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piston failure


HASTY

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thanks rebelbanshee2 i was about to go on a two day trip when i decided to change the O rings on the exhaust because of a little leak ,just happen to look up the port and f*ck me,look at that !.on my back with torch and camera trying to get pic so i can get some sort of help and all i get is bullshit answers like yours :angry:

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after now getting the top off (rebelbanshee2 ) we can see better, any clues? have a shaved head and advance timing plate,thought it might be detonation seizure before because i'm running standard pipes and it might have got hot ? but why only one side ??changed main bearings 6mnths ago, thought seal would last longer !stator side.left hand carbie top still tight ! :confused: now cannot up load pic like the last one because it cannot up load this type of file ERROR<ERROR WAS FOUND :confused::confused:banghead:confused:

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The problem is on the edge of the piston, at the exhaust? If there is a hole in the middle of the piston that would be detonation, caused by high compresson with low octane. If the edge of the piston is ate off and looks scuffed like your picture. The biggest culpret would be heat. With hot weather and running hard the piston doesn't have time to cool off.

You also said this only is on the left side. That says your crank seal was leaking, leaning out and running hotter. Also look at the intake boot to see if there is any cracks. Or the seal on the reeds to could be leaking.

With a two stroke there can be two or three things contributing to the problem all at once. Like not enought oil in gas, low octane, high compresson, air leak, or somthing restrickting the gas going to that sides carb. If you just rebuilt the motor did you make sure the end gap on the rings was .012 to .018 ? I could go on, but check these out and get back if you still can't find anything wrong.

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Hasty, you have people trying to help you, but calling people out saying they are giving B'S answers isn't right. Stop taking B'S photos for us to look at and you'll get a non B'S answer. Take the cylinders off the pistons and take another photo. Then we can tell you what the problem is.

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sorry but i cannot even tell thats an engine from the picture. :confused: Before you took it apart you should have done a leakdown test. I guess you could put the head back on to see if the crank seals were leaking. If the melted spot is in the middle its pre-detonation. if its near the exaust port its a lean condition. scuffs on the side could be a cold sieze.....

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  • 5 weeks later...

my apologys to those that thought i was a bit agressive in my behavior,i had a pisser of a day and am now over it, i am replacing the crank seal ,maybe it was due to extreme advance on my timing (new timing plate ,stator,from ricky!!! yer go ricky)did not change jetting from standard.also got stock pipes ( not letting heat escape maybe ?)also the top of my LH carby i've being having trouble with.(getting TORS removal kit) not sure if i should go single carby ? also the exhaust ports are worn around the o-ring seating area,so i need to fix that also!.

i'd like to thank you guys for your input and ideas :cheers:

from what i read. it seems to have been a combination of things.lean fuel maybe, detonation due to the damage done to the top off piston (advanced timing ?) cold seizure maybe due to exhaust leaks ?

any way putting it back to gether as best i can and hope it runs again :clap:

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Cold seziure is from not letting the bike warm up properly before riding, are you putting new pistons in and what about a boring it? or just honing it maybe? i would say that it leaned out though.

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i'm just replacing the one piston , this will be ok yer ?with a little hone,not much damage to cylinder

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