m in sc
Well-known member
watched the whole video. here's what i think happened. i think they were gapped too far, and you were getting blow by, and then pumped allt he oil out of the motor. i would guess the exhaust pipe was oily. i think the cyl is actually ok. you can get a ball hone and clean it up. make sure you clean it with brake cleaner.
bottom end is probably just fine. but yes, rise it out. mineral spirits are good for that.
the melted section at the top on the intake side is interesting. its def melted. But, it doesn't look to be a lean blow up. If you look under the piston dome, a lean blowup will show a bright white or ashy color to the aluminum, that's from heat at the dome that can be caused by lean or detonation. the tiny bit i could see looked dark, so that's good. pretty sure it got hot due to lack of oil and blowby, expanded, and caused the seizure. where are your afrs sitting? they need to be int he 13~13.5 range, 12~12.5 at wot.
as many motors and pistons as i have killed over the past 3 decades, that leads me to beleive thats what you are dealing with. Ive blown up lots of 2 strokes due to timing, and air leak lean conditions, IMHO, thats not it.
I would think you can hone the cyl, get a new piston and rings, probably a new small end bearing, and put it back together. put at least 50-60 miles on it before going wot.
as far as the piston hitting the plug, i'm running a slightly shorter plug in mine. its an old grom one i had, lower heat range but its shorter, don't have the number handy but i can get it.
.02
bottom end is probably just fine. but yes, rise it out. mineral spirits are good for that.
the melted section at the top on the intake side is interesting. its def melted. But, it doesn't look to be a lean blow up. If you look under the piston dome, a lean blowup will show a bright white or ashy color to the aluminum, that's from heat at the dome that can be caused by lean or detonation. the tiny bit i could see looked dark, so that's good. pretty sure it got hot due to lack of oil and blowby, expanded, and caused the seizure. where are your afrs sitting? they need to be int he 13~13.5 range, 12~12.5 at wot.
as many motors and pistons as i have killed over the past 3 decades, that leads me to beleive thats what you are dealing with. Ive blown up lots of 2 strokes due to timing, and air leak lean conditions, IMHO, thats not it.
I would think you can hone the cyl, get a new piston and rings, probably a new small end bearing, and put it back together. put at least 50-60 miles on it before going wot.
as far as the piston hitting the plug, i'm running a slightly shorter plug in mine. its an old grom one i had, lower heat range but its shorter, don't have the number handy but i can get it.
.02
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