Why does my 450 seem like the floatbowl is running dry?

[Frostbite]

My 450 runs prety well. I have a GYT pipe, K&N filter, ect.

I was in the mountains yesterday carrying a 250 lb passenger and when I would hold the throttle pinned form more than say 20 seconds (maybe 30) the ATV would start missing and lose power if I kept the throttle pinned.

It's like the float bowl is running out of fuel. If I stop and wait a minute I can keep the throttle pinned for another 30 seconds before the same thing happens again.

Have you guys messed with your float level?

Has Yamaha put out any TSB on this problem?

Thanks for any help you can provide.

Frostbite

 

[Glenn]

I'd be willing to bet you may have a little gunk in the carb bowl or something in your main jet.

 

[fireman69]

mine was doing that, i could putt along just fine but if i tryed to go 1/2 throttle or better it would spit and sputter, i have mud in my bowl, the carb breather is in a bad spot and will pick up gunk easy, just clean the carb and your good.

 

[ctateusa1]

another thing to do is to reroute the carb vent up above the air intake to keep junk out of it.