edgehanger Posted September 27, 2011 Report Posted September 27, 2011 So i know the rings broke because they were in the pipe. Banged up the head. Second bike i seen with the exhaust side of the piston being eaten away. The other bike had no broken parts. The piston on both cylinders was losing weight on the exhaust side. Your analysis? Also not a scratch on the cylinders in both bikes. http://i1176.photobucket.com/albums/x336/edgehanger/100_0085.jpg http://i1176.photobucket.com/albums/x336/edgehanger/100_0084.jpg Quote
Dahl87banshee Posted September 27, 2011 Report Posted September 27, 2011 So i know the rings broke because they were in the pipe. Banged up the head. Second bike i seen with the exhaust side of the piston being eaten away. The other bike had no broken parts. The piston on both cylinders was losing weight on the exhaust side. Your analysis? Also not a scratch on the cylinders in both bikes. http://i1176.photobucket.com/albums/x336/edgehanger/100_0085.jpg http://i1176.photobucket.com/albums/x336/edgehanger/100_0084.jpg If it was bored out at all and they didnt smooth the exhaust and intake ports the rings would catch and break. Idk what the process is called but they put an angle back on the port so it isnt sharp and the ring doesnt grab Quote
blast off Posted September 27, 2011 Report Posted September 27, 2011 If it was bored out at all and they didnt smooth the exhaust and intake ports the rings would catch and break. Idk what the process is called but they put an angle back on the port so it isnt sharp and the ring doesnt grab Its called champfer when they smooth out the port edges. if the exhaust side of the piston is damaged its most likely from an air leak causing it to run lean, probably crank seals if the motor is older and they are the originals. I just had the same issue with the exhaust sides smoked and the crank seals were leaking. either way no air leak is good, check all seals including reed gaskets. Hope this helps. Quote
edgehanger Posted September 27, 2011 Author Report Posted September 27, 2011 oh yea i forgot to mention. The engine has no leaks. Seals are good. Trying to figure out why this happened before i put it back together. It would still run but it was popping and wouldn't rev right. So i thought it might be a reed because it was sucking through the tail pipe a little. Changed the reed and same thing. So i took the pipe off and poured out rings in my hand. It doesn't have a fresh bore. i think its the first time this engine ever been opened Quote
Larry's Shee Posted September 27, 2011 Report Posted September 27, 2011 (edited) How do you know you had no leaks? What kind of oil you using? Might just be worn out. Finish draining coolant before you pull jugs. Edited September 27, 2011 by Larry's Shee Quote
edgehanger Posted September 27, 2011 Author Report Posted September 27, 2011 How do you know you had no leaks? What kind of oil you using? Might just be worn out. Finish draining coolant before you pull jugs. Because i did a leakdown test and it would hold pressure for ever. Worn out is about the only thing i came up with too Quote
Larry's Shee Posted September 27, 2011 Report Posted September 27, 2011 Was just asking. Being it's never been torn down eliminates overly wide exhaust porting. Any idea how many hours on it? Quote
edgehanger Posted September 27, 2011 Author Report Posted September 27, 2011 Was just asking. Being it's never been torn down eliminates overly wide exhaust porting. Any idea how many hours on it? It has alot of hours but it held up well. Look like the rings got caught in the exhaust port judging from the only marks on the cylinder were around the exhaust port. Rings are also seized in the piston (whats left of them). Maybe it was leaking a little coolant in there. Steady eating away at the piston bit by bit. Quote
RadarRacing Posted September 29, 2011 Report Posted September 29, 2011 (edited) THAT IS LEAN. Exhaust side melts first , smears aluminum all across rings sticking them to the piston , scrapes cylinder. Do NOT just rebuild and start it back up without finding out what caused the lean condition. There is also absolutely no wash on those pistons , you will also see the very black color of the pistons, that was a pretty lean bike. There should be wash marks next to the transfers where the incoming fuel keeps the piston sort of washed clean and shiny. That sucker is just black as hell. Edited September 29, 2011 by RadarRacing Quote
edgehanger Posted September 29, 2011 Author Report Posted September 29, 2011 THAT IS LEAN. Exhaust side melts first , smears aluminum all across rings sticking them to the piston , scrapes cylinder. Do NOT just rebuild and start it back up without finding out what caused the lean condition. There is also absolutely no wash on those pistons , you will also see the very black color of the pistons, that was a pretty lean bike. There should be wash marks next to the transfers where the incoming fuel keeps the piston sort of washed clean and shiny. That sucker is just black as hell. the piston does show some overheating on the underside of the piston. What would lean it out though with no air leaks? Dirty carb? Crankcase had a small amount of oil on the side that blew. Piston doesn't have any wash on it. Why not? Quote
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