Honda ATV Forum banner

TRX 450 sputters and backfires when i get on the throttle... HELP

23736 Views 32 Replies 7 Participants Last post by  FOXRIDER3361
I have an '06 trx 450 ER. I took it out the other day and it ran fine for a couple of minutes, then it started to sputter and backfire out of the exhaust (shooting flames out of my HMF pipe) it feels like i lose a bunch of hp. So i replaced the spark plug, COMPLETELY took the carb apart and cleaned the sh*t out of it. I cleaned the air filter and its still doing the same thing. It starts up just fine and i can roll into the throttle and its not nearly as bad as when i hammer down on it. Can anyone help save my weekend of riding?!?!
1 - 10 of 33 Posts
I'm not real sure about the 450 carb, but on most carbs the pilot screw or the air screw is located on the bottom, toward the front of the carb.
i just took it out for a run and it seems just a little bit better not much. i didnt mess with the air screw yet. the only screw i see is on the left side of the carb under the fuel line and when i unscrew it, fuell leaks out from one of the vent lines below it
That's probably the drain for the bowl.

Try looking at the same level as where the bowl meets the carb body. I'm thinking it's on the same side as the fuel line hooks to the carb, right on the corner of the carb.
Look at this drawing. It's the one labeled "pilot screw".

See less See more
You're stll not jetted right. the air/fuel screw only effects the idle. It won't do anything for your rpm range.

Try going to the next step up on the clip, see if that helps or makes it worse. You may need to go up on the pilot.
Yeah, I agree with Red. All the mixture screw is for is to get a smooth idle.
Make sure your engine is cold when you check the valve clearance.
I doubt that much difference in the valve clearance would matter as far as running. It might make the rockers tap a little.
Make sure you have a real strong blue spark at the plug. A weak spark can make them act like that, sometimes.
Hey, I just thought of something else. Maybe your accelerator pump is bad.
This is the accelerator pump.

See less See more
If you want to send me your email address in a private message, I will send you the whole section on the fuel system from the repair manual, unless you already have a repair manual.
1 - 10 of 33 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.