Here's how it went down;
I'm running Bill's bored 34mm flat slide Mikuni, the HMF pipe with a Yoshimura quiet tip wrapped in glass, and the KDX200 big snorkle. After I got the pipe to give the proper amount of sound (experimenting with different tips), I had the backpressure I would be jetting to match. Again, with several trials of experimentation, I found a good set-up for the combinations I'm using. The pipe dB is perfect for street use.

Bumped pilot jet from 37.5 to 40
adjustable T handle air screw at 2 turns (may try 1.5 today)
Stock needle one notch lower on the pin (one notch richer)
Main Jet is a 137.5, up from 127.5 that is standard in the flat slide.

Bike pulls like a 350. A small hesitation from 4k to 5k, which I think is either the airscrew setting, or the needle. I'll try adjusting those, but I think the jeting is at 95% perfect right now.

I am offering this info for those using Bill's flatside Mikuni and a pipe, this should get you ball park, and further testing for your altitude will get you spot on. We live at 1400 ft.

 

Bake, I ended up fairly close to your settings which makes sense since we should be about the same altitudes. With this set-up my bike pulls from idle through redline with no hesitation anywhere. It does seem kind of odd that mine ended up needing a way smaller pilot jet, especially with the amount of air that it is flowing.

My set-up:

Free mods, Muzzy full system + quiet core, no snorkel, 6 holes in airbox lid 1/2" diameter, K&N air filter.
140 main jet
30 pilot jet
Clip in position 1
Fuel screw 1 turn out

I had my carb jetted by a bike shop in town mainly due to lazyness on my part. They have an old dyno to load the bike on and and use an O2 sensor to get the mixture correct. I took it out today and it ran flawlessly.

 

I changed back to the original pilot, 37.5. It was hard to start on the 40. I have the needle one notch richer than stock, airscrew at 2 turns and the main still 137.5. It starts, idles, and pulls through the gears up to 7k in 6th gear just as it should. Above 7k I'm not likely to see very often, but it should be fine, as the main is thoroughly in control by then.
Tommorrow I will adjust the airscrew a little by little towards 1 1/2 turns just to experiment, but I'm real happy with the way it runs now.

My guess is, the bike needs stock or even leaner jetting off the bottom, the 250 cc cylinder just doesn't create enough suction at idle/just above, to breath in all the intake/exhaust is capable of. Once it's up and turning some R's, like on the needle, it can utilize additonal flow, thus it can handle more fuel.

Now that I think the jetting for the snorkle/stock engine, and HMF/quiet packed tip is correct, I'm going to throw the shorter pump rod in the mix, and see what it changes. The stock pumper rod only works through about half throttle. The shorter rod will run the pumper all the way to WFO.

So, at most, I have about 2-3 carb pulls/re-installs left to go[sm=burnout.gif]

 

Bit of a continuation from this thread: https://www.kawasakiforums.com/m_119..._2/key_/tm.htm

Worked on the jetting sporadically over the past couple of weeks, I too think that I'm in that 90-95% range.

Here's where I'm at:

Mikuni TM34
Muzzy full system with quiet core and spark arrestor
KDX snorkle, no backfire screen, K&N filter
de-smogged, external crankcase breather
#140 MJ
#37.5 PJ (johnny, you sure you're using a #30?) (tried a #40 and had a rough time with idle)
needle clip set to 4th position down from top
fuel screw for best idle (probably around 1 - 1/2 turns out)

Still have a flat spot around 1/8th throttle, but I have a Q-0 needle jet and an assortment of air jets to play with
(I think I'll need the Q-0 when I remove the airbox lid again)

My 331cc kit arrived today, but it'll have to sit on the shelf until I get back from Thailand at the end of April

 

I had time to get mine out for some riding tonight andthat extra punch off idle really came in handy. Was riding some muddy ruts amd needed the extra pop to get out of trouble on several occassions. Needless to say am very happy with the upgrade.

I will be sending Bill a check for the t-handle fuel screw tonight.

 

bake, could you let us know how that shorter rod works? on a side note i'm running the same jetting you are and i'm at 260ft. the small hesitation i get is at or right above 5000 rpm's. and i only get it once in a while. it's very random. i'm thinking about shimming the needle to see what happens. at 5000 rpm's i think i'm off the pilot and on the needle so shimming it might get rid of that stutter.

 

I didn't do the work, but that's what my mechanic told me. I thought that it sounded small too. It's running good and he jetted it using an O2 sensor so will let well enough alone. It cost almost $200 for the work so if I have any problems it's going back.

Where are you guys running for RPMs at idle. If I drop mine below 2k it will die. Not sure what it's supposed to be.

 

Maybe that small pilot is the idle problem. Try the stocker, as idle speed is affected by the pilot and the airscrew. Idle on these engines should be 1100 rpm, give or take. Sure, the O2 meter say this.that. But you 're the final say, because you are using the engine under actual road conditions. Theres no way I'd settle for a 2k idle and pay some guy $200 bucks. That carb ISN"T set up right if you need a 2k idle. Period.

 

O2 sensor is not accurate for setting the idle jetting. Better to use Eddie Sisnero's method if you have an idle screw that can be adjusted while it is running like the Kouba t-handle screw.

http://www.thumpertalk.com/forum/sho...d.php?t=327405

 

+1 i have my idle right around what bake said and its fine.something is definately not right.



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