KDXRIDER.NET

Hello everyone, first time post, got a new to me 04 KDX220, replaced the piston and kit with help from KDXRider, thanks everyone.

Now I need to troubleshoot a slow or low speed stumble.

Idle's good, but from just off idle to 1/4 throttle it has a stumble. By stumble I mean it doesn't run smooth and hesitates just a little. 1/4 to WOT it runs great. I have removed carb twice and cleaned, cleaned both jets with a small wire, tried adjusting pilot screw, no help.

It's completely stock, only mod I have done is remove the airbox tube, it has new plug, new piston and kit, it stumbled before piston and kit, it has stumbled sense I purchased from previous owner about 1 month ago.

Other question I had was is the stock air filter cleanable or throw away/replacement type. I looks stock, anyone recommend a K&N?

Any suggestions?

For the stumble you need to go thru the jetting procedure in the "Jets and needles" section. What is your current jetting? You will probably need to go down a size or two on the pilot.

As for the air cleaner it is cleanable if it is in good shape. Or you could get a new pre oiled filter for $15-$20.

As far as the K&N, do a search on here. There was a topic not too long ago that went over this, and over, and over, and over it.

Sounds like a rich pilot jet. You may need to re-jet...especially if you are on the stock jets. For now, try turning out the air screw on the carb in 1/8 turn increments. You might find the happy spot that way.