KDX 220 slight miss coming off idle

[Roadking]

Hello everyone, I'm a newbie here. Just bought a new 2004 KDX 220 from the dealer here in Raleigh, NC. Main reason I bought the bike was because of all the great things you guys had to say about the bike. It is the perfect bike for me (45 years old and not being on a dirt bike in years). I've put about 50 miles on the bike around the farm and at a local MX course near here. I can truely say that I love the bike :). But I do have a question. There seems to be a slight miss in the engine right off idle. As soon as the pipe starts to come in it runs great. At idle it purrs like a kitten, it's just that little miss starting off. Thought it might be the plug so I changed it, but that made no difference.

If this is just how it is that won't be a big deal. Just checking to see if that's normal.

 

[bereal]

The stock pipe is set up for the upper end of the rpm range. Spend the money and buy an FMF Gnarly pipe and silencer, some Boysen pro series reeds, and re-jet the thing and it will scream! The problem sounds like you are running too rich for the altitude and air temperature you are riding in. Try dropping the needle 1 position and maybe a 40 pilot jet. Sounds like you are to rich on the bottom end of your throttle.

Eric

 

[John Harris]

I agree. Put the carb needle clip in the next to the top notch, thus lowering the needle and see where you are. Then you will probably need to jet. Your current problem is probably the result from a too rich primary. Think of it like this--the engine is hesitating till it gets the too much fuel cleared out. Enjoy, and you will not believe the difference when it is right. John

 

[john_bilbrey]

Agreed, jetting right made almost as much difference as my Gnarly pipe. While you're in there, ditch the airbox lid (at least the snorkel and put some holes in the top).

 

[kmccune]

Ditch the air box lid first, or just the snorkel and drill holes in the lid. Search this forum and you will find pictures of the various snorkel/lid combos people have come up with. Now try it out again, it will most likely be a lot better. Go to Canadian Dave’s http://justkdx.dirtrider.net he has a jetting guide under the tech tips section. Study the jetting guide until you have a bit of a feel for it and then search this forum for KDX jetting in your area, there will be a difference based on the mods to the bikes and the rider, but you will be able to get a base line. The temp will effect it as well so include that in your jetting parameters when coming up with a base line. Now after your happy with it buy pipes and reeds and porting and big bores....... :)

 

[03KDXHOPPER]

The Airbox lid is a must anyway... If you want to ride with the factory pipe, it sounds like the pilot circuit is what you're looking to check out. New pipe=new carb settings all over.
The clip position affects holding at half throttle. The problem happens before that point, so I wouldn't mess with your needle clip just yet.
2 adjustable Parts to the pilot circuit: Air screw, and throttle stop (idle screw--black, grippy). The air screw is brass and just below (on 220 I think) the idle screw.
My experience in missing off idle has taught me that it could be too rich OR too lean. Turning the screw IN will richen the pilot circuit. OUT will lean it. With your idle set where it is, durn the screw IN until you hear it starting to sputter. That's when you've gone too rich. If you've gone past 3/4 turns IN to get to that point, turn it out 1/4 from the "sputter" point and try that. Adjust idle if neccesary. If you hit that "sputter" point right away, lean it by 1/4 increments until you get the desired off-idle. Hope that's a start.