The carb from 06+ is that same from what I know, so that kit should work. The #2206 kit for KLX300 also works (I and many others have it).

 

I may eventually spring for one of those DJ kits. For now, I am trying to get jetting closer with what I have, as others have. I thought I would try adding another 'spacer under the needle, I had already added 2 small washers, decided to see what would happen if I got more aggressive. I placed a tiny o-ring, like from an o-ring chain, in addition to the washers. I did not test ride immediately, rather, and stupidly, I rode it in to work the next day, about 5 miles. At 1st there was a minor surge at constant speed. Then noted losing power while climbing hills. As it continued to warm up, it constantly surged, and performance deteriorated even more. I was actually concerned it would not get me home, so I opted to hitch a ride with a co-worker to get my truck and trailer it home.

Once I got it back in garage, found the plug was very black and sooty, so obviously I went way too far with my needle 'shimming'. I removed the o-ring under the needle, and replaced it with a much thinner third washer. Also cut a coil from the spring. I have read people suggest cutting 2, but decided to stay conservative.

Results? It seems much more responsive, surge seems to gone, and even revving it up some and getting on it, there is no hesitation whatsoever. Since this is a fresh rebuild, I am still staying on the conservative side with the throttle, so have not tried quite WOT or over 7-8k (I don't buy that 'keep under 4k ist 600 miles' yeah right) But I think may be getting there. I will put some miles on and check my plug again.

Now, question, does the min jet ONLY affect near WOT? If so, the pilot and needle may be close, but I am not so sure on the main, but would seem I would be on the rich side with a 128, considering all else is near stock (aside from 300 kit). Once I have some more break in miles on it, I will venture into WOT territory to see how she responds up there, and I will keep tabs on that plug.

 

There is some overlap... but in general: 0-1/4 is pilot circuit. 1/4-3/4 is needle. 3/4-WOT is main jet.

 

Grrrrr.....I hate carbs! EFI is the way to go. But no, Kawi wanted to keep this old mule basically as it has been for the last 15-17 yrs. Old fashoioned carb when the competition, (Yam for one) went EFI. Although, overseas gets EFI on this bike, why not North America?

Anyway, enough ranting. So, I thought I was getting close. While my bike 'seems' to run ok, the plug again indicates very lean. It was completely white. I can beleive it, too it 'sounds' lean. Meaning upon accel that sharp ping is still there. Maybe that is characteristic of this engine? Seems wrong.

I guess I am going to order a DJ kit. I emailed them, they admited they have no kit specific to my application they recomended the one for the KLX 300. They did not offer custom settings though, just said that I should start with the settings as described in the instructions. So, I wil be experimenting again. We will see.

 

I think the guys overseas who are ditching thier efi for carbs due to the inability to tune for big bores and other big power upgrades might disagree.


On your jetting issues - some people have had success with adding a larger jet and shimming the needle but it seems far more people are disappointed with the results from these cobbled together "jet kits".

The stock needle is a piece of crap, made for emissions and the choked up intake and exhaust and will most likely never be good for anything other than a completely stock bike.

 

Yeah I have read about that as well. Until someone comes up with a tuning chip or something that is...

I hear you there. I guess I am one of the unlucky ones. It is just surprising that I am getting two extremes, rediculously rich, or really lean. By rights I should be overjetted across the range. I am going to blame the needle.

Looking at the stock needle, I would have to agree. I suspect that the DJ and even the stock 300 needles for that matter must have much more aggressive profiles, and with big(er) bores comes the requirement of bigger fuel requirments mid range, which is where I think I am lacking. The stock needle is probably just too flat to make shimming workable in my case. Maybe on a stock 250, but must not satisfy the breathing requirements of a 300. As for the intake, that is an easy fix (change to KDX or ditch snorkle altogether), but a new $400 exhaust is not cards for the near or distant future. I may try to mod the OE, I do have some welding skills. But at the least it should deliver decent low end tourque performance, and satisfy my desire for a quiet bike. I am not expecting to wheelie from corner to corner. But just hoping to at least get closer to optimal air-fuel ratios for reliability and rideablilty.

 

See if the info here will help out for showing how the CVK works: Care & Feeding Of The Keihin Carb.

It's for a CVK40 but our CVK34 is virtually the same. There is a jet/throttle position graph at the start of Part II that is useful to visualize the operating ranges of the various jet circuits. Helps to narrow down where your problem may be occurring. Hope it is helpful for you.

 

Ok I got my dyno jet kit that is made for the klx300 for my 250s. Im gonna install it later tonight and have been reading that you need to cut some of the slide spring off?? Or do I just keep it the same length?? I have the normal mods done to mine. FMF header and silencer, UNI airfilter, KDX snorkle. What you guys think on the jetting with these mods?

 

Is it the DJ #2206 kit? Mine didn't call for cutting the spring, but instead enlarging the hole on top of slider a little. If you don't want to cut the spring, some other poster suggested using mini zip tie or something to zip a few turns of the spring together. Then if you don't like it, go back to the way it was.

 

I never did thank you kansas-klx, I read through this, and it was very informative.

I was thinking about the DJ kit, but they dont have a kit specific to the 2007 250s, although they recommended the stage II kit for the KLX 300, as many othes have. The emial reply I got from DJ did not offer any recomended settings, clip positions, etc. Reading the literature on that kit, the stage II kit is intended for use with no snorkle, and afermarket exhaust.

I felt that kit would have offered too-aggressive a jetting curve for my application. I am retaining the stock exhaust, and want to keep a snorkle. I like a quiet bike.

So I opted to get a kdx snorkle, and a N1TC needle and associated clip/collar. The latter added up to around $20 online, much cheaper than the DJ kit.

Once I got the stuff in, I took both needles and compared them with a micrometer. Interesting, as the N1TC needle is actually larger in dia than the stock needle. I was surprised by this. I am guessing the needle-jet itself on the 250s is a bit smaller than the KLX 300 CN version (not the US version), thus needing a slightly slimmer needle. But, it seems to work out.

I swapped the needle, and at first I put the clip on the 2nd groove. It seemed a little more responsive, but not earth shattering. I did a quick speed run, and I got up to about 78mph (indicated) before I backed down. It would have certainly done alot more, but I was on a narrow country road, not an interstate. Plus, at that speed, it was feeling a little too 'light' and twitchy for my tastes. But I think the performance is what I should expect with a stock exhaust, and I should be pleased. I have read about people having a hard time maintaining 65, I would bet I could maintain a steady 85 if I wanted.
But I was getting a bit of a flat spot around 4-5k, so decided to check the plug after my little ride. Completely white. So decided to pull the needle and place on 3rd clip. Now, this may seem aggressive, but keep in mind, I did not change the needle-jet, still have the slightly smaller (I am guessing)
stock needle-jet, so not as rich as some of you might think.

I got to ride my bike into work this am, about 45deg F. It started great, settled into a perfect idle, and pulls away very smoothly at all throttle levels, even low and slow. No flat spots that I could detect. And near WOT seems like it just wants to keep pulling. I could not detect any popping on decel either. So I think I have it about as close as I am going to get it, without changing anthing else (like needle-jet or exhaust).

I may still try the upgraded needle-jet #16017-1368 at some point, but I am pretty satisfied with it as it sits.

I found another thread https://www.kawasakiforums.com/forum...s-clicks-6305/ I will go and add my bike, specs, mods, etc. This was another good and informative thread.

Oh, and I also installed the KDX snorkle, a bit louder, but not bad. Does feel like it is breathing easier.