6 Sigma Racing Carb kit
 

Anyone using the 6 Sigma Racing Carb kit?
Thought I'd give it a try
Ebay has it for $39.50 and it comes with airbox mods and jets and needle adjusters.

I bought this kit from eBay. The carb jetting information is good and the kit is pretty basic, but it will get you started. Their jets are OEM Keihin and they provided 3 main jets and 1 pilot jet. The needle adjusters are washers which you stack between the bottom of your slide and the top hat of your needle to raise the needle up to enrich your midrange. The airbox mod is to drill holes in the top of your airbox and/or remove your snorkel.

I think that if you ask the jetting wizards here on the forum... the magic is in the needle profile. I know they have found one of the OEM needles that works almost as well as the DJ needle... it's in one of the threads, don't remember which.

If I was going to go with OEM parts, I'd just buy them seperately and using the jetting advice on this forum... otherwise, you can't go wrong with a DJ kit.

Most of those who have done it (not me) reported that shimming the klx needle doesn't do much and the 6 Sigma kit for the KLX is a sham. If you want there's a $0.02 washer at Ace Hardware to shim the needle. Keihin jets should be a few bucks each at your dealer or local dirt bike shop.

If you want a jet kit for the KLX, go with dynojet which comes with an adjustable needle, a range of main jets (no pilot) and good instructions (none of which call for cutting up your air box), or get the KLX300 (Keihin N1TC I believe) adjustable needle and Keihin jets.

That's my 2 cents; enough for a needle shim washer!

I used the largest main jet from the 6 Sigma kit, but had to order a larger (38) pilot jet from jetsrus. I used the .02 washer from the hardware store instead of the shims in the 6 Sigma kit because I only wanted to use 1 shim, and with the 6 Sigma shims I would have had to use 2. I did not drill the slide or the airbox either, and just removed the snorkel, so I didn't need the drill bits provided.

I pretty much followed the instructions on the link below to clean and rejet the carb. It also tells you which .02 washer you need and where and how to buy it, it actually cost .15.

KLX250S Home Page

I wanted to keep my KLX as stock as possible and simply make it run better. Drilling a hole in the slide, cutting the slide spring shorter or even installing an aftermarket exhaust was not in my plans and still isn't. Lifting the needle with the shim does enrich the midrange because it opens the main jet sooner to allow more gas to flow earlier from the main jet. Does it flow as well as a Dynojet needle? Probably not.

I agree with the poster above, buying the jets and washer separately will save you some money, and you really don't need the 6 Sigma kit.