no offensse taken fab, I understand that the piston doesn't have piston locating pins for the rings. what i was thinking was that if the ring wasn't compressed all the way on assembly it could have got caught on the bottom of the cylinder, and if the cylinder was forced on it could have damaged the ring land. i wasn't trying to knock the detonation theroy, i just felt that that was more probable because of the condition of the top of the piston, and he said that the cylinder looks ok.

 

ok I have to partialy correct myself. I didn't look at the pic's close enough to see the first ring land broken. thant was broken when the engine was running, my bad. but, i still feel that you would see signs of detonation on the top of the pistion and between the first ring and the top of the piston. it could have been simply part failyer. just wanted to correct myself before i made myself look a d***.

 

yeah im not ruling anything out. its really hard to pinpoint EXACTLY what happened. just gotta look at the obvious first. and with detonation being a known problem with the stock head TB kits, its a very good possibility.

 

I agree, is it possable that it's running to rich? because that could cause it to detonate past the rings which would account for the scoring on the piston. does that sound posseble?

 

highly unlikely. actully running lean would cause detonation, not rich. rich could cause washing of the cylinder walls which could cause scoring though. my guess is that scoring was caused after the ring lands busted and the piston was no longer being guided by the rings.

 

That is not detonation. If it was the top of the piston would be pitted. Are those pistons cast or forged? I'm going to assume forged because it looks like you have had minor cold seizures (never a full seizure though) from the amount of scraping on the side of your piston, which would be from reving the **** outta the bike and the piston expanded faster than the cylinder did and it scraped, cause the ridges to break off. Warm your bike up before you ride (stockers it doesnt really matter because they are cast). Now have you ever had the bike just seize up on you and then a little later you went back to ride and it was fine? Then that really indicates you had cold seizes. Now if its cast piston ignore what I said.

 

very possible. but to flat out say "its not detonation" without holding the parts in yer hand or doing the damage yerself is a pretty bold statement. so many possibilities.

 

I just talked with Mike at TrailBikes, the pistons are cast so I dont believe cold seizure to be the culprit. He said that the pistons are made exactly as stock Honda pistons and has never heard of any kinds of trouble with them. I think Im gonna agree with Fab on this one and rule detonation as the culprit.

 

either way, i'm gonna order one the end of this week/next week...w/ the oil pump...