Ahh, well, it's easy to answer your question, and I'd be happy to.. It'll probly only take a few days to get you "up to speed" on the CVK internal circuitry, dyno charts "101" , etc..
If you really want to learn enough to understand why a DJ140 is needed for lidless running near sea level, with stock header + slipon, send me a PM and we'll "dig in"..

In the meantime, if you want to duplicate my dyno tuned 22 hp, targeted 12.8:1 AFR @ WOT, you'll install the slipon, pull the airbox lid, and install the DJ kit as per my recipe - 140/2N. That is what I offer - a dyno created/tested setup for max power with a slipon or a full exhaust system.

About the 128, I found early on that the KLX will run just fine with horribly screwed up fueling curves. Based on what the Dyno showed me, and my phone calls to DJ's "tuning experts", I have to assume the DJ kit and its' instructions (using the 128) are responsible for decades of poorly fueled KLX's. They developed the kit for use with stock exhaust - install a slipon/full exhaust/pull the lid/perform the MCM and you're "off the DJ reservation".. More importantly, apparently no one ever bothered to put thier KLX on a dyno to see what was going on with the fuel curve !!! This is the reason I did my testing, no one had verified numbers on a dyno tuned KLX - now we do.

 

Is it possible they are using the Keihn main? 128 is the richer jet used in the cheap mods. I used a 125 and the Dial-A-Jet.

 

I don't know what you're talking about - who is "they"..?

From RageHard's JetsRUs site, https://www.jetsrus.com/FAQs/FAQ_mik...ihin_sizes.htm, a K128 main would be horribly lean - equivalent to a DJ120..

 

From my experience with my 2009 the first mod I would do is get the DJ kit and re-jet for no snorkel and stock exhaust. You will feel a (relatively) big gain in overall performance compared to stock. Adding a slip-on, and again re-jetting, will add a little more power over the stock muffler but with big increase in exhaust noise. I have both the FMF Q4 and DG-R mufflers and the DG-R gave the biggest boost in midrange power (5500-6500rpm), but it is loud! I think that the mid-pipe diameter of the Q4 is too large -- it moves the peak torque higher up in rpm even with the stock header. I also have a Powerbomb header, but I think unless you are running lidless the stock header gives better mid-rpm performance.

The KDX snorkle is not worth the expence and the trouble. It is still too restrictive and it is more difficult to get the jetting correct -- I could never get rid if the surging at steady throttle at mid-range rpm cruising. And, when I removed, it the bike really woke up.

The biggest performance gain is Klxter's lidless and full exhaust mods. It is a big gain over stock, but intake and exhaust noise increases significantly!

When I bought my KLX it came the KDX snorkel, FMF Q4/powerbomb, and the stock exhaust so I got to try many different combinations. The biggest performance gain at the least cost from stock was the DJ kit stage 2 with the stock exhaust. That is what I would do first.

 

That "they", someone doing jetting in a youtube video is using a 128. The cheap mods using Keihin jets uses a 125 to 128 for the hop up w/pipe and large snorkel, maybe lid off.

 

Kehin 128 is way too lean for lid off. I used a K150 with Q4, stk header, lid off. And for Q4/ Powerbomb with lid off I used a K158. I also found the the N1TC needle is too rich for for lid off -- I ended up buying a DJ2152 kit and using that needle to get my KLX to run right lidless.

 

Wow, Pika, you got some insight ! You pretty much hit the nail on the head with your observations.
I have a few questions:

Is your CVK running a drilled slide? Stock or DJ slide spring?

Reason is, the N1TC on 1N in concert with a stock slide lift hole and the stock slide spring should handily keep AFR from going too rich in the low to mid range with your 150 or 158 setups - meaning great throttle response and TRQ ramp-up below 6.5k.. One the other hand, if you are "mixing and matching" slide springs with an oversized lift hole.. For instance, a DJ spring on a biggy lift hole will tend to overfuel the low/mid regardless of needle and clip setting..

Have you seen PWJM's thread on the DJ228/ N1TC/ stock needle measurements ? - https://www.kawasakiforums.com/forum...-teaser-43153/

The N1TC has a practically identical taper to the DJ228 - but it is shorter overall and the distance to "start of taper" is shorter. BUT, it has a thicker straight section. Add this all up, add in a large main jet for running lidless, and you have to run the N1TC on the top two notch's (1N, 2N) ..

I assume you are not running the MCM..?

 

No MCM mod. I am thinking of doing it a some point.

My slide hole was drilled to 7/64", so I am running the stock spring. I tried the DJ spring and would get a big hiccup under full throttle acceleration. But, last night I filled the slide hole with JB and I going to drill it to 2.5mm today.

I tried the N1TC-1N, stock spring, drilled slide with both the K150 and K158 setups and I could not get strong acceleration below 7000rpm. Below 7k when I opened the throttle either part or all the way I get kind of an over rich blubber. Not exactly like a too rich main jet blubber -- it is more subtle than that, but there is a definite lack of power between 6-7K. That is why I bought the DJ kit to get the needle -- which did not eliminate the blubber. I know I can get rid of it, because using lid/no snorkel, K138, N1TC-2, stk header, DG-R the blubber is not there and I get strong throttle response from as low as 5.5k up to about 9k or so. That is my favorite combination to date because of the great torque at mid rpm, but the sound from the DG-R gives me a headache when I ride more than a couple of miles on the street. In the woods its not so bad, but on the street it is terrible. I may try the K158 setup with stock hole, stock spring, N1TC-1 as you suggest -- it is worth a try.


Yes, have seen PWJM's thread on the DJ228/ N1TC/ stock needle measurements My findings are similar. N1TC: .098 shank, .053 tip. DJ288: .095/.050. Stock: .096/.052. Measured with a micrometer. Length wise DJ288-4 is equal to N1TC-1.

 

I agree on all counts.
The "thing" I don't know is the powerband of non MCM. I did the MCM as my first mod on a totally stock bike - so I really have no data or experience without it. However, I have always assumed that TRQ production below 7k would tend to be weak. The DGR, as you know, by way of its' small dia. midpipe, will help make TRQ in the lower range, but I've wondered if that should be the goal on standard cam timing.. My thinking is that if the engine wants to make TRQ up higher, perhaps THAT is what should be enhanced - with Powerbomb + Q4 + lidless...? It does also get into riding style/preference, but you gotta wonder what HP numbers could be found at 9-10.5K with such a setup..

Anyway, with a standard hole and spring, N1TC or DJ's DN0228 on 1N , Pbomb+Q4, lidless, K158, should really scream!

I almost hate to say this - the stock needle will run your "K158 setup" very well also - the DJ spring will move its' fueling curve low enough in the RPM range to fuel the low/mid range well instead of too lean. I did not dyno test such a setup, but I did run it for quite a while before settling on the DN0228 @ 1N (DJ144, lidless, Megabmb+PC4).. Fud fer Thot..

 

Length wise DJ228-4N is equal to N1TC-1N

Armchair tuners oughta chew on that a while - then add to your chewing the larger diameters the N1TC carries throughout (compared to the DN0228 needle in the DJ2152 kit) ...

It gets cerebral folks - I could use yall's enhanced frontal lobes..