Hi I have a 2003 220 I think its stock, it has a stutter at low revs, it feels like a misfire/ over fueling.
It pulls well at high revs.
So far I have changed the plug, cleaned the filter, refilled with new petrol with a 40-1 mix .
It is running a 42 pilot with the air screw at about 2 turns out. when the screw is in it dies but as the screw comes out there is little change in the revs.
Help the dam thing is starting to get to me .
Jono

What altitude? What weather conditions? Did it used to run better, or are you a new owner of the bike?

Sounds like a slightly rich condition under load.

Personally, I would try turning the airscrew out to 2.5 turns or putting in a 40 pilot and see if it helps.

Some amount of stutter at low revs is inevitable IMO, especially if you're at a low throttle opening... The exhaust resonance just won't work there so the bike runs a little funny. Gas it!

If it sounds like a miss but is running fine it's just a 2 stroke but if you got a loss of power or seems like it gets over a certain rpm's then takes off you got a problem. Don't know where to tell you to go first, it could be many different things. I would start with a carb cleaning if it has not had one recently and check the reed valves well you got the carb off and check the numbers on the jets to make sure they are stock since it has got no mods. I seen some other guys in a other post talking about not repacking silencers can cause loss of power in low rpm's, i would like to get more info on that myself. good luck

Well I have just got back from my local Kawasaki off road dealer he tried the bike out and said that it was running rich and said change the pilot jet and may be change the clip , he had a look at the offical Kawasaki parts book and the 2003 KDX220 should have a 38 jet but mine is a 42.I'm going to get one and see what happens.
Thanks for all the input so far.
Jono

Let us know as this seems to be a 220 trait , not common on a 200 .

Well I have changed to a 38 pilot and it's a little better but not much.
Any more ideas out there, I'm off to my local Kaw dirt dealer today to see if they have any ideas. I'm getting into the mind set of giving up with the bike now, so If any one in the UK wants a 2003 KDX220 drop me a line.
Jono

Don't give up on it as once you sell it and the next person finds the right combo to make it run better you'll regret your impatience.

I've spent an entire summer tuning a H.P. Honda four-stroke but when I hit the right cam timing , jetting ect. it was worth every minute. Yes , I wanted to throw it over a bank many times up to that point.

Did you know Edison made over a hundred light bulbs before one worked ?
How many of us would have given up way before that.

Slide cutaway also plays a big role in low end response.

Unfortunately, slides are much more expensive than pilot jets.

You can grind material from the bottom of your slide to get more cutaway and lean out the low rpm range. Grinding is cheaper than buying a new slide (or a new bike, lol).

Hi I hear what your saying and yes your right it's just that I'm married to high maintenance and complex I just wanted my other ride to be a bit more simple .
I spoke to the guys at the local MX shop and they rode it it and came back saying that it was running rich and lean at the same time, when the the slide comes off the stop it runs rich to start with but then starts to lean untill it opens over the 1/4 to 1/2 mark, they suggested that I should lift the needle to the 3 clip and try that.So I now running 40-1 38 pilot 3rd clip and no snorkel I have yet to ride this setting but I will let you know how it goes.
As for Mr Edison ,it is said that he once told a reporter that actually had 3,000 attempts to create the lightbulb. When asked about the failures he said "I didn't fail 3,000 times. I found 3,000 ways how not to create a lightbulb"
So looking at that I'm just finding ways of not making a KDX run right Thanks again Jono