thanks, so... if the needle is really what your paying for cant I just buy the stock 300 needle from a local shop? Whats the advantage of purchasing a DJ jet it...seems like a pretty expensive purchase to me? This whole drilling a hole or using a shorter spring thing really kicks me in the rear...how could the two be so different yet have the same end result? Am I understanding that correctly? I read the instructions on the dyno site and their instructions are about like anyone elses....which aren't too good. They have a top view draw of the carb and it says several times to drill "holes" (pluraral) yet it shows and points to a "hole" (singular) yet shows pictures of several holes and tells you to be careful not to drill certain holes out. I'm like "WTF???" I'm not a big modder, never have been..but I wan't to untap and open this pig up a bit because I can feel from riding it its restricted. Like I said, to me it feels almost like its being choked or governed. Like it wants to give a bit more power and snap, but the factory stole it away. If I can just do that I'll be relatively happy. At times though I wish I would have gone with the DR 650 I was looking at the same time as this bike. But between price and weight I went with this one....but I woulda had 2 1/2 times the power.
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SUZUKI GSX250FX

 

Depends on what you want. The DR650 is a great bike, but it rides like a tank compared to the KLX. If you ride roads and open fire roads, either bike will do, but if you ride technical off-road and single track, you'll most likely be a lot happier with the KLX.

As for the hole vs the spring, the slightly larger hole allows a little more air to pass through, thereby allowing the slide to lift faster which equals a little better throttle response. The slide fights against the spring to do this. If instead, you weaken the spring by shortening it and reduce the initial preload, you end up having the same effect, it just happens by a slightly different method.

You wouldn't want to do both, though. It would be like drilling too large of a hole which would have the effect of quicker throttle opening, but it would most likely hang up there when you let off and not come down quickly enough.

 

aaaah, yes , makes perfect sense. Thank you. Now that you explain how it all works, sounds like dyno jet has quite the little racket there. sell you a few jets, a needle and a spring and charge ya 63 bucks for it..........yeah right.
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AMATEUR ****

 

The value-add from Dynojet is the needle, and to a lesser degree that they packaged up all the jets for you with the most common sizes and instructions that are known good for the bike, tips for jetting at various altitudes, etc. But you can only get the Dynojet needle from DJ and while I haven't personally used one, it has a unique taper that you can't get anywhere else and is tested specifically for the bike it is sold for usually with racing applications in mind. So that's where the cost comes from - the engineering and testing behind it.

When I got my KTM, I bought a James Dean jet kit which is a similar idea as with the DJ with 2 custom needles, jets, etc, and it is awesome. Far better than the stock setup and well worth the $75 for me. I know it is apples vs oranges, but the idea is the same. So I wouldn't discount the Dynojet kit, it has been tried and true over the years on the KLX300, which is very similar to the KLX250S.

 

Save your money. Get a "N1TC" (KLX300) needle from your Kawa shop, with clip and collar (important.) While you're there get a #128,#132 main jets.
Fit it up to the carb', needle set in the middle clip, #128 main (try first before #132) and set the fuel screw 2 turns out from lightly seated. Keep the stock #35 pilot jet. Pull out the snorkel from the airbox lid (leave the lid on.) You should get change from $30.
This WILL add performance to your bike pipe or no pipe.

 

Oh yeah!
WTF! Taking the tank off to change the spark plug. Use the plug spanner in the toolkit supplied with the bike. Comes out easy as pie.

 

Thanks for the info sounds much better. 128 though, that sounds like a big jump...what about a 120-125 first? For something as small as just removing the snorkel I can't see how making a jump clear to 128 is prudent. I mean, its got a 118 in it now right? Its a U.S. bike, pure stock.


And yeah... I used that wrench, couldn't get it out for crap. The tank is RIGHT above the top of the wrench, those hoses are in the way and I can BARELY get my hand in there to use my fingers to twist it out after I break it loose. I mean, unless you got small hands or wire fingers, I don't see how its possible. And I figure I have average size hands so..............
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Bmw 600 History

 

What altitude do you ride at? How far are you above sea level? That's the biggest thing when determining the jet to use. I'm at about sea level and never ride more than a couple hundred feet above, so the air is very dense down here. I'm running the 128 main jet with 2.75 turns out on the screw and all I did was take out the snorkel. When I get a full exhaust I'll probably jump up to the 132. Also don't forget, these things come VERY lean from the factory... that 118 is ridiculously too lean. I'd recommend starting at the 124 if you're higher up than sea level. If that's too rich then you might jump down to maybe a 120 or 122.

And +10000 for Nobrakes... that's what I was trying to say and utterly failed :P You pay the money for the R&D on that needle. My dad has the JD jetting kit for his DRZ-400, it comes with two needles, main jets, pilot jets... all kinda neat stuff. And none of it would work together without the expensive R&D. I think $65 is money well spent for the increased power and driveability the DJ kit gives you, but that's just my .02

 

Is drilling out the Mixture screw plug and re-turning the mixture screw really necissary? Stupid question: yes, but im trying to gague how difficult this mod is (more like what the odds are i screw up my ride)

 

Yes it is. The A-F screw on mine was only about 1.25 turns out from snug; DJ recommends closer to 3 full turns out. Its not hard to pop out the cover. You use the drillbit and drill a small hole into the little cover, then you screw in the provided screw and pull out the little cover.

I wouldn't stress about it so much, fairly simple. The hardest parts are wiggling the carb out and back in. The rest is simple unscrewing stuff and paying attention to where things go when you take them out. We did mine in a few hours (including breaks).

Plus you've got wonderful KF folks to help you if you get stuck.