Dirt in Carb?

Ok, I have a problem with my 2002 WR426. I seem to be getting dirt in my carb/jets somehow. It doesn't seem to be coming in through the air cleaner as the tubing between the filter and throttle plate are perfectly clean, not a spec of dust. Yet when I open the carb there is dirt inside. How? All my vent tubes are factory length and hang under the bike. I clean/oil my filter every other ride. It isn't even that dusty where I ride. The bike will run fine for weeks then it will suddenly get a bad fuel problem and won't get better until I take apart the carb and clean it all. HELP!!!

Have you check you gas tank and your gas can. Sounds like you've got something floating around somewhere?!

If the dirt "Inside The Carb" is in the float bowl, install an in-line fuel filter. That'll prevent dirt from entering with the gas.

dirt coming in between airbox and rubber snorkel that attaches to the airbox?

You can pull the rubber snorkel off of the airbox and silicone the seating surface between the two.

I have a similar condition. I get dirt in the top of the carb. Doesn't seem to affect performance or clog any jets. My airbox and tube are clean. Could air/dirt come in from say the choke or Hot start circuit? Another possibility might be from around the intake bell but that seems clean also. I don't think it is coming from the fuel but I should put in a filter to be sure. Never thought of it. Thanks


If the dirt "Inside The Carb" is in the float bowl, install an in-line fuel filter. That'll prevent dirt from entering with the gas.

Actually, no it won't. I had an in-line filter on my YZ and still got dirt in the carb. There is already a screen in the petcock, just so you know. Make sure the airbox to carb clamp is nice and tight- I'd recommend replacing the phillips screw in the clamp with an allen head screw- you can get it a lot tighter without having to worry about stripping it that way.

Don`t hang the breathers under the bike by the back wheel,the wheels are throwing dirt at them all the time,this is where the dirt is getting drawn into the carb,run them up under the tank.

I agree with NH. You must inspect your air boot carefully. These boots are notorius for separating from the airbox and sucking in dirt and water. It can ruin a motor pretty quick.

All very valid points,I also would add if you have a DR. D hotstart,inspect that as well.The junction where the cable comes in the carb (at the threaded nut) Dirt seems to find its way into the hot start curcuit.My .02 cents :)

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