All 2st Mikuni to PWK Jetting

Could someone please advise on a pwk equivalent to my mikuni settings?

01 wr250 totally stock except needed walts heavy powervalve spring to fix a bog

Mikuni
380 main
no 4 slide
60 needle 4th clip(from bottom)
float lowered to max 22mm I think
32.5 pilot 1.5turns

Keihin
172 main
jd red 4th clip (from bottom)
float level with base (15mm I think)
42 pilot 2 turns out.

I have no real problem with mikuni after walts spring, however when chasing the bog i got the pwk and would like to give it a fair go as I feel it has more grunt but just seems rich everywhere compared to my nicely jetted but temperature sensitive mikuni.

pwk sputters just off idle pulls hard through mid and is very slightly sputtery up top if your not aggressive with throttle, pilot still seems too big as won't easily hold idle nor die as I turn out airscrew but dies easily when I turn it in. I'm going to try lowering float level to 18mm as a low float really cleaned up the mikuni

fwiw Australian fuel seems to need much leaner jetting and I am at sea level riding between 15-35deg celcius

As long as the float is level I would suspect you are too rich in the pilot. As you adjust the air screw leaner from one turn out does the idle go higher and higher? If so you need a smaller pilot jet. Don't be afraid to experiement with leaner pilot jets. On a KX I used to have I ran a 35.

i agree, here in oz seems we require a much leaner jetting. i would do some plug reading, also found the slide has a lot of influence on off idle crispness. i ground the slide back on both my wr125 and wr360 tmx carbs seemed to clear things up but do a plug read first.the slide grind was increasing the size and depth of the crescent cut out.

That is the jetting I have in my wr250, but your Mikuni jetting was a touch leaner than mine was.

I was 390 60 middle and 32.5 pilot 2 turns.

I'd drop the needle and the Pilot one size.

Excellent good to hear I'm close. Didn't want to run red needle in leanest clip as it's not really the right needle if I need to do that plus it's not real hot here yet.

Maybe should try cel or eel so it can run more in the middle

Seems odd that so many people need to run the leanest needle fully lean.

The red JD in leanest slot is perfect at the temps you are riding. If you want more hit from the bottom use CEL in second slot. If you run a lot wot then i would go for the EEL to get maximum horsepower, but it,s a bit rich at light throttle at those temperatures you are running. I use the EEL for iceracing only. If you have bludder at light throttle go for the CEM. I use a 40 pilot and 175 main. Very good!

Johnny

I run the red needle all year 'round.

Actually, the PWK mixes clean almost all the time.

I throw in 1/3 race gas in the Winter.

Top slot in the CEL needle and 38 pilot for a 2010 wr300, yours sounds like it would be far too rich but check the plug first. The CEL needle gives cleaner and more progressive bottom end than the JD red. I have tried the JD blue needle but it didn't suit the tight woods/technical type riding.

Ok so will try 40 pilot and cel needle by the sounds of it. Main area the mikuni was better was off the bottom so hopefully that will fix it, thanks for your inputs

If the Mikuni feels better off the bottom the Keihin must be very wrong jetted;=).

True, but I wonder if other setup factors make a difference. fwiw I run 50.5mm bottom stop, 22mm float to bring the bottom end out even using the mikuni. The keihin should still be better but maybe it makes a bigger difference when the bottom stop is 48mm

Update

Did a decent ride on the weekend

42 pilot, red needle leanest clip, 172 main 3 turns on air screw

Felt a bit doughy in first 5 mins compared to mikuni but was great after 5 mins and we rode from 30deg c to around 10 deg c with hugely varying humidity and it never seems to change one bit. Also its deceptively fast, my mates wr290f was working pretty hard and mine was idle to midrange, nothing even close to full throttle.

If your airscrew is 3 turns out your pilot is too rich. Try dropping to a 40 and you'll probably find the airscrew needs turning in slightly. It will give you a crisper bottom end.

I dont think you should be adjusting your PV to suit the carburation or make of carb.

Must be a misunderstanding. Have long had a huge midrange bog that jetting never effected, the only thing that went vaguely close was raising the bottom stop. This gave ok mid but killed bottom end and top end was still savage. Walts stiff spring fixed all this. When chasing the bog i got a pwk, now I've fixed the bog and am fine tuning the pwk.

Will get 40