[Spunky1031]

Just rebuilt my 04 f7 efi 250 miles ago and now it burned down both pistons. Had oil to the oil pump but didn't bleed the pump. I was adding oil, so it was using oil and was also premixing. Wondering if it could be a bad fuel pump or if anyone would know what it could be? Sled would also sometimes dog out at 7000 rpms, so I am assuming that is a power valve issue or if the two could be related.

 

[cc335]

wouldn't think it to be bad fuel pump or power valves. Maybe bad crank seal. Sounds lean.

 

[RJ Gleason]

Can you show us good pics of the pistons?

 

[kccats]

No oil? Bad seals? But both going down could even be bad gas?

 

[Spunky1031]

It was using oil, and other sleds filled up with me. No pic of piston, but they both were blowing holes down the center until one gave out on one of the sides. Exhaust was grey and clean all the way to the can.

 

[RJ Gleason]

Super lean condition then.
How were the throttle body mount flanges?
Otherwise I'm thinking fuel mapping is wrong.

 

[Spunky1031]

Looked good. Thinking of testing the fuel pump to see if it is getting enough fuel. Can a Arctic Cat dealer hook up to the computer and test it?

 

[whyman]

You might of put the gaskets on wrong when you put the jugs on. Did it idle high before it blew. Could of been a bad seal between the case and jug.

 

[whyman]

sounds like it was running lean.