Bet ya thought it was to my Raptor huh LOL

no, i was at the lake and i was riding my tri-z hard and then all the sudden it lost compression and i tore it down to discover there was a hole in the top of the piston!!

what caued this because i need to make sure it doesnt happen again.

i was thinkin it was from maybe a rich condition or maybe to hot gas not sure but any info would be great
thanks

 

Too lean and/or detonation, too rich won't get hot enough to hurt anything.

 

Ummm Stock Piston 9.1 + 111 octan = Hole in pistion. [img]i/expressions/face-icon-small-tongue.gif[/img]

 

Been there.. Definatly running lean.

 

Where was the hole?? Close to the center or around the edge???

 

smack in the center

and stock compression 6:1 i think

it might be pretty lean I got quite a bit of porting done to it

I did the phase 1 the cylinder and maybe more i went a little crazy, i also added the intake boost port shown

 

How long did it run before it holed the piston? You could have blown a base gasget and that caused the lean condition. That happened to my sons WR a couple of years ago at Pismo.

 

I have seen a torn carb boot do this. Do a pressure check once you get er back together.

 

i had a 490 main in it and im it ran SO SO SO good maybe i need to bump it up with the porting and the open lid and small scilencer

 

Engines running lean will make great power until they melt. Id guess it was very lean. Did you ever take a plug reading?