I have a 04 Raptor 660. I got a hmf silencer for it, I rejetted it and it ran great. I took it on a muddy trail ride, half way through the ride it started to sputer and die. When I got it home I found the air intake runer coming from the air box to the carb had slipped off. My carb sucked in some muddy water. So I took the carb apart to clean it out. When I go it all back together it started, and idled just fine but when I get on the throtle it just starts to sputer and go bop, bop, bop. Its not getting enough fuel or air. Please help if you can, the race season starts this weekend

 

that happened to me once too after i took apart my carbs and cleaned it. when i hit mid throttle it spuddered and almost died. well this is what i did wrong. i put 2 of the jets in the wrong/opposit places. the needle jet and starter jet. one of the carb has 3 little jets in it. you might have gotten 2 of them mixed up. i did and i had the sameproblems as you.
good luck

 

After I rejeted it it ran great for about a week then I got dirt in the carb. so I dont think I jetted wrong. Thanks tho any thing will help I'm going to burn this F**king thing to the ground.

 

Did you try cleaning the jets?

 

yea i would take apart the carbs, take out the jets and clean with carb cleaner really good. i would evern clean inside the ports where the jets go. i sunk mine in a deeper mud hole than i thought it was and i had the same issues and mine is rejetted too. if you took your jets out to clean them,, with all due respect, you might have 2 of them swapped. i did that and it would not run good. also i would check your electrical connections on your CDI box that might have gotten wet too considering it is almost next to the air filter.