cylinder question with pics

[Justin_l]

Yesterday I went riding and it started smoking as soon as it did i loaded it up in the truck and brought it home. I tore it down last night and this is what i found. I would love to have some of your opinions on what caused this? Is it a messed up rod or crank? There were no broke rings and no scaring on the piston or rest of the cylinder besides this white part. There is a slight grove where this white part is. Thanks for the help in advance.

http://i223.photobucket.com/albums/dd117/Justinmatthewl/PIC-0133.jpg
exhaust side ^^^^
http://i223.photobucket.com/albums/dd117/Justinmatthewl/PIC-0134.jpg
Intake side ^^^^^

[Jason Hall]

Kinda looks like you were sucking In some water. Is the piston real clean on the exhaust side? Antifreeze or water will usually clean the carbon off the top of the piston. Is the white spot just a stain, or is It grooved Into the cylinder? The exhaust side of the cylinder Is most deffinatly going to be hotter than the intake side, so It's probly just where the water was getting squeezed against the hot cylinder wall when the piston came up on compression stroke.

[Justin_l]

There is a slight groove where the white part is ... there was just some oil residue on top of the piston.