My King cat may have a fuel problem??

[King Cat 06]

I have an 06 King Cat EFI, I had it around home and rode it a few times (SE Minnesota) and it ran fine then on a warm day it was sputtering and backfiring. I just assumed it got hot that day. I just took the sled out west to montana and it ran good one day then sputtered and backfired the next. Any suggestions of what this is? I have an exhaust can on it for a 2005 model king cat, shouldn't make much of a difference being they are the same motors.
I did talk to a mechanic and he suggested that it may be the filter valves in the bottom of the gas tank that are not opening enough and its not getting enough fuel and causing this.
Any suggestions? Thanks

[DamageInc]

You might want to put the stock exhaust back on and see if the problem goes away.

I doubt that it's the check valves (aka "smart valves"), but I suppose it's possible. I would check out all the sensors to make sure they are in spec, and check fuel pressure (ideally check them when it's running crappy, not good). I'd also take a good look at the plug wires. If one has been rubbing, you could be shorting out intermittently. Sometimes they will work fine until they get some powder flying under the hood, and that moisture helps them short.

It should almost go without saying, but did you bypass the throttle safety switch, to make sure that wasn't causing it? I've seen ignition key switches cause that too (they wear out and the contacts open intermittently), but I've never seen it on that new of a Cat.

[King Cat 06]

I will try the exhaust first. I have a feeling that is what the problem is being there are not many miles on the sled. (5-600). If that doesn't work, I will check the plug wires, it does seem like one of the plug wires may not be snapping on tight. thanks for the input

[Da-Roc]

I had the same problem on my 1998 zr600 efi cat. It turned out that the oil tank outlet was clogged with a bit of thick oil. Clean the oil tank out and blow out the lines. A mechanic told me to filter out any oil out of any new gallons of oil I buy. He said there is no telling how old the oil is and 2 cycle engine oil settlels in the jugs over the summer. It also settles in your oil tank. He said if the oil turns gooey in the bottm of your tank you would never see it until you empty it out. I cleaned my tank out and the darn thing screams like new now. I use a paper paint strainer and it helps tons.
Da-Roc

[Red Setter Man]

push the thorrottle lever into the pivot from the end. The thorr. switch maybe giving up the ghost