Here's a couple of pis of the piston out of Raptor03s engine.
Top
Bottom
It's hard to make out the crack on the top and there's no signs of it being melted on top.

 

Is that a 12:1 ?

~HoundDog

 

11:1

 

What made it do that?

 

Dam thats not good... I guess its time for a big bore kit..[img]i/expressions/face-icon-small-happy.gif[/img][img]i/expressions/face-icon-small-happy.gif[/img][img]i/expressions/face-icon-small-happy.gif[/img]

 

There's allready a 12:1 in it and running strong. I posted the pics because there was some talk of octane and jetting with an 11:1 piston. This one was running on 91 pump gas and I think that was the main reason for the problem. It's hard to see in the pics but it looks like it cracked and then developed the small hole.

 

Here's another pic of the top Click

 

I think 91 should be fine with 11:1 ... no ?

 

I wouldn't recommend it. You might get away with it for trail riding when your WOT for short periods of time, but drag racing up long dunes and the problem the stock raptor carbs have of not flowing enough fuel for the bigger jets, you'd be asking for problems. Low octane and a little lean is a bad combo, especially on long runs.

 

Could you use 93