250-500cc 250 / 300 / 360+ Jetting Database

After a 4 day ride l have noticed pinging when cruising at 4th, 5th and 6th gear@50% throttle with no noticeable pinging in 1-3rd or at WOT at any gear- sign of the too small pilot jet or too lean clip height?
Mostly happens on flat service road @500mt (1600+ft) above sea level @12-15C.
My suspicion is crappy fuel or mixture of different oils and ratio (10 riders and each rider used their own brand and at different mix ratio).

Any...properly warming up the 360 and l enjoyed a foulplug-free weekend YaY!!!

Year & Bike Model = 2000 WR360
Carb = KEIHIN PWK 39MM
Pipe & Silencer = Stock
Other engine mods = Opened up inlet manifold
Premix ratio & fuel type = 40:1 Castrol TT
Temperature range (deg C) = 15 to 25C
Elevation (metres) = 500-800m
Main jet =175
Pilot jet = 40
Needle = DEL
Clip position = 2nd
Air screw setting = 2
Slide = 55? That's what it says on the slide but it doesnt correspond to any part for 38-39mm PWK that I can find.
Spark=BR8EIX
Conclusions/Results = After tossing the TM, getting a used PWK and using the database as a starting point , I'm almost there. Initially I put a DDK (top clip) in but it ran rich off idle and I had no room on the clip to go leaner. The DEL cleaned it up nicely and I have more room to go lean. Even though I think it is still slightly rich, the beast starts easily, goes hard from idle to 'holy $%^#!!!',doesn't smoke, doesnt foul plugs and uses less fuel than it did. Awesome!

Today we had our first day at the ice. We plowed a very nice track and i did some jetting changes for evaluation today.I thought it should be colder but we had around zero. My WR 300 has the Keihin PWK 38 AS. Standard pipe. My jetting was as follows:

EEL needle in middle clip, 182 mainjet,45 pilotjet,1,5 turns out. We ride at 1000ft.

Conclusion. Starts fine and idles good. Before the bike was really warm and i had cleared it out with a few WOT runs it had a slight bludder. When on full pace it ran faultlessly. This needle feels very good on the ice because it is not too explosive from the bottom, so you can get on the throttle smoothly when you exit corners or just keep constant smooth powerslides. Very controllable. Unfortunately i got a puncture after 10 laps as the screws in my tires had rubbed a hole on my hose:foul: The tyre is fixed with a reinforced bicycletire outside the hose for protection, and a race cylinderhead is on it´s way, so i get back with more info later!


Johnny:sweden:

Hi guys this whatsworking me for me in uk's freezeing cold weather -13 here today.Year & Bike Model = 2001 WR 250
Carb = pwk 38 non as
Pipe & Silencer = stock
Other engine mods = rebuilt motor
Premix ratio & fuel type = 50.1 Rock oil K 2
Temperature range (deg F) = minus 13
Elevation (feet) = 350
Main jet = 180
Pilot jet = 45
Needle = DDL
Clip position = 4th
Air screw setting = 2 1/4
Slide = 6
Conclusions/Results =Very Snappy off the bottom and revs clean with no pinging. With a little smoke. Ive tried DDK, DDJ CEJ and settled on DDL if anyone has any better suggestions on the needle please pipe up and let me know. I've also tried 40 pilot witch was to lean then a 42 pilot which also to lean and ended up with 45 pj nice easy starter now. For the main i tried a 178 but the plug showed a bit lean and now runs better with a 180 main.

Year & Bike Model = 2009 WR300
Carb = Keihin PWK 38mm A/S
Spark Plug = BR8ES
Pipe & Silencer = Pro Circuit Plat. 2 and 296 silencer
Other Engine Mods = none
Premix & Fuel = 32:1 (Klotz R50) with 91 octane

Temperature range (deg F) = 30 to 40 degF
Elevation (feet) = 500 - 2000 feet
Main jet = 178
Pilot jet = 50
Needle = CEK
Clip position = #1
Air screw setting = 1.5 to 2 turns out
Slide = stock from PWK for 99' CR250R
PV Spring Combination = OEM
Conclusions/Results = this combination worked great at my house (300' ASL and temps nearing 50), but the lean needle position failed miserably at the forest with cold temps and varying elevation. The 50pj and 178mj were what the motor needed, but I had terrible fuel starvation on the needle.

I have never been real happy with how the bike transitioned into the midrange and always thought it was a too rich condition on the needle, but now I'm thinking its a lean condition. I'm going to try this same combo, but with the needle in the #3 clip next time and see if midrange improves.

The 178 main pulled like a madman on top. I had forgotten how fast this motor was!

Wr300 jetting

I have not seen a jetting database thread stickied here. I think it would be a nice addition to this site to help provide a common spot for collecting everyone's jetting and results.

Here is my proposal. You can copy/paste this list into your reply.

Year & Bike Model = 2009 WR300
Carb = Keihin PWK Airstryker Quadvent 38mm
Pipe & Silencer = standard
Other engine mods = none
Premix ratio & fuel type = 40:1
Temperature range (deg F) = 6 to 25 degrees Celsius
Elevation (feet) = 0-500
Main jet = 175
Pilot jet = 40
Needle = standard supplied with Keihin carb
Clip position = #2
Air screw setting = 1.25
Slide = standard as supplied with Keihin carb
Conclusions/Results = After a lot of playing around with the jetting this is just about right. The best pilot size was 38 with the air screw at 2.5 turns but i was concerned it was too lean, so I upped it to a 40 and backed off the air to 1.25 and it is good - snappy response. Midrange is strong and top end seems good but needs more testing. I was running a 170 main jet but it was peaking too early and the over rev was flat, so the 175 main is a must. I did try a 185 and that was too fat by a long way. I am being pretty picky as the jetting as I currently have it is pretty darn good, but I am searching for perfection. I reckon a 180 main is going to be too fat so I will try a 178 next. The bottom end is good so I will leave that alone, midrange is good also, so it's the top end I am searching perfection for.

Hey guys,
I'm heading out to a race Arizona next week. My current jetting in my PWK for 5000-6000':
JD jetting red needle 2nd from top
168 main
stock pilot
air screw 1.5 turns
Bike runs great!!!
Arizona will be 2000-3000'. I was thinking of going to middle clip on red needle and switching the main to a 170. What do you think?
Thanks

Year & Bike Model =2004 WR 250
Carb = Mikuni TMX 38
Pipe & Silencer =atm stock, tomorrow FMF exhaust pipe with stock silencer
Other engine mods = All stock
Premix ratio & fuel type = 95 with 1/50 Ester oil
Temperature range (deg F) = 30-68 deg F
Elevation (feet) = 40 feet
Main jet =390
Pilot jet =35
Needle = 60 (stock)
Clip position = middle
Air screw setting =2 turns out
Slide = The stock one I think its a nr 3 slide..?
Conclusions/Results =It works good for me. If I accelerate from gear 1 to 2 to 3 the front end comes up really easy without using the clutch, just throtle wide open. If I accelerate from standing still in gear 3 to max it pulls straight to max speed.

Now I read alot about people changing to a Keihin PWK carburator. I read that everyone feels a lot of difference. But I can't imagine that between a mikuni and a keihin is so much difference.

Can someone tell me the exact differences between a mikuni and a keihin. And why a keihin is so much better than a mikuni?

Nota bene: Husqvarna is still mounting the mikuni's on the 2010 and 2011 models. So if a keihin is really so much better, why does'nt husqvarna mount the keihins stock on it?

Year & Bike Model = 2010 WR300
Carb = PWK38 AIRSTRYKER
Pipe & Silencer = STOCK
Other engine mods = NONE
Premix ratio & fuel type = 50:1 MOTUL 800
Temperature range (deg F) = 30C
Elevation (feet) = 0 -400
Main jet = 180
Pilot jet = 38
Needle = RED JD
Clip position = TOP
Air screw setting = 1.25
Slide = 7
Conclusions/Results =

Runs clean at the bottom end, but the only way I could get 1/2 to 3/4 clean was to set the needle to the top clip which seems a bit odd. I might try a 175 main and raise the needle one slot. or maybe try the blue needle. I have only just got the carb so it is interesting to play around with but already the bike runs much crisper than it ever did with the TMX.

Year & Bike Model = 1996 WR360
Carb = KEIHIN PWK 38MM AS
Pipe & Silencer = FMF Gnarly and FMF Powercore
Other engine mods = Walt's Air Boot mod
Premix ratio & fuel type = 40:1 (Silkolene)
Temperature range (deg C) = 18C
Elevation (metres) = 0-100m
Main jet =170
Pilot jet =38
Needle = JD Red
Clip position = 3rd
Air screw setting = 1 3/4
Slide = #7
Conclusions/Results =
Just did the top end and changed to the Red needle to check the difference. Well, l like the low to midrange that the RED gives compared to the Blue, a little bit of spooge @1 3/4 and 3rd clip but not worried as the bikes has only 30mins into a top end but will go 2nd clip and play with airscrew once l get to the mountains again.
The airboot mod is hard to say at the moment as l haven't give it WOT for too long but it did feel like the transition from 3/4 to full and stronger felt like the clutch was slipping except for the roost

Year & Bike Model = 2009 WR250
Carb = Mikuni
Pipe & Silencer =Stock
Other engine mods = none
Premix ratio & fuel type = 32:1 and 91 octane no alcohol pump gas Motorex oil
Temperature range (deg F) = Missouri ?
Elevation (feet) = actual altitude is 1000 ft.
Main jet =440
Pilot jet = 45
Needle = "Gay Needle"
Clip position = middle or 3rd from top
Air screw setting = Stock ?
Slide = stock
I purchased new Pilot jet, Main jets and the new needle from Hall's Cycle thru Clint. I was having problems with being to lazy thru bottom to middle RPM, so I talk to Clint and he told me to rejett it so I did. It fix it, but now I'm having problems with it after I've been running it for a while it does't want to start if I was to kill the motor. I started with the clip in the 3rd position then I drop it to the 4th position and still does the same thing. If anyone knows what it could be please let me know.

Eric @ P3/Pirie Performance Products here!
Year & Bike Model =2009 WR 250
Carb = Keihin PWK 36mm (from Wyatt Seals)
Pipe & Silencer =Stock
Other engine mods = None
Premix ratio & fuel type = 60:1 Motul
Temperature range (deg F) = 45-65F
Elevation (feet) =Sea Level
Current Jetting:
Main jet =165
Pilot jet =42
Needle = DDJ
Clip position =3rd
Air screw setting =1.0-1.25
Slide = 7.0
Conclusions/Results =Carb came from Wyatt Seals with the jetting posted in another thread which I posted below.
162 MJ
48PJ
DDJ Needle (3rd Clip Pos)
AS-1.5 Turns out
7.0 Slide
The bike ran very rich through all throttle positions, tried a few different needles which were
CEJ, and CDL and different pilots and mains. Wound up with the current jetting and the bike does now rip. Very smooth crisp power and I can't see changing anything except the main to a size bigger for some our deep sand riding here in Southern New Jersey. In our tight woods the thing is quite impressive, it reminds me of my old 98 Honda CR250. I am a former top A level rider in our local Enduro assoction and can still get it on just not for 80 to 100 miles. I think that jetting that Wyatt Seals sent with the carb is based on a Pro Circuit exhaust system and some serious engine work by Wyatt and Pro Circuit and also Glen Kearney being one of the top riders in the world. That jetting was to wierd for my skill level. Wyatt had said the 36mm carb will give a little bit more low end torque then the 38mm. I've also put a two tooth bigger rear sprocket on as we do most of our riding in true east coast tight woods. One last thing that is off subject from jetting. I installed a Magura juicer clutch and that has been very good too along with my own protection products. Cheers!

Year & Bike Model = '09 WR250
Carb = Mikuni TMX38
Pipe & Silencer = Stock
Other engine mods = None
Premix ratio & fuel type = 40:1 with Premium pump gas (no ethanol)
Temperature range (deg F) = 70F
Elevation (feet) = 6,500 ft
Main jet = 360
Pilot jet = 27.5
Needle = 6BFY43-74 stock
Clip position = 3rd
Air screw setting = 2
Slide = Stock (#4 I think)

Conclusions/Results = I had tried all main jets from 390 to 460 and the power still dropped off at the upper end. Against conventional wisdom and service manual recommendations I kept going down on the Main (partially inspired by lankydoug's results). It gradually revved further out until with the 360 it revved all the way and now has good power and runs clean throughout the range. I was still getting alot of spooge with the 30 pilot. I adjusted the powervalve closed setting to 50.5 mm at about 45 hours. It was off from the factory (it was about 48mm). It made it even richer off the bottom. I was getting alot of spooge and it was harder to start. I went down to the 27.5 pilot. Awesome results. Great power everywhere. With the 30 pilot I had spooge running halfway down the silencer after a 15 minute warmup ride. The next day with the 27.5 pilot, after riding (mostly 2nd gear) singletrack for over 2 hours I had spooge no further than the endcap and it ran great.

Year & Bike Model = '09 WR300
Carb = PWK38
Pipe & Silencer = Pro Circuit plat 2 & 296 silencer
Other engine mods = None
Premix ratio & fuel type = 40:1 (Klotz R50 Chevron 91 pump swill)
Temperature range (deg F) = 55-65F
Elevation (feet) = 1000 ft
Main jet = 175
Pilot jet = 42
Needle = CEL
Clip position = 2nd
Air screw setting = 3/4 turn out
Slide = stock??

Wow! The mid and top are crazy strong with the CEL and the 175 main. I'm not sure if the low ene lost a little or it just feels weaker cause the mid and top pull so hard now. It is VERY sensitive to air screw adjustments now, but I think that 42 was a little lean for now and will perform better in the summer. I had to constantly fiddle with the air screw to keep it rich enough down low, but good grief does it pull hard. Borderline too much power.



Year & Bike Model = '09 CW125R
Carb = TMXX 38
Pipe & Silencer = FMF Fatty & stock shorty silencer
Other engine mods = None
Premix ratio & fuel type = 40:1 (Klotz R50 Chevron 91 pump swill)
Temperature range (deg F) = 55-65F
Elevation (feet) = 1000 ft
Main jet = 460
Pilot jet = 35
Needle = stock
Clip position = 4th
Air screw setting = 1.5
Slide = stock

Yes, yes, yes, yes, YES!
Basically bone stock jetting, but the needle @ clip #4. Bike now rips! Rode both moto and woods over the weekend and I was in small bore heaven. It's true that the RM needle just does not work with the stock slide.

This was my 3rd ride on the bike and 1st ride where it actually ran right. I believe the hype and the bike is super fun.

Year & Bike Model = 1996 WR360
Carb = KEIHIN PWK 38MM AS
Pipe & Silencer = FMF Gnarly and FMF Powercore
Other engine mods = Walt's Air Boot mod
Premix ratio & fuel type = 40:1 (Motul800)
Temperature range (deg C) = 13-22C
Elevation (metres) = 500-900m
Main jet =170
Pilot jet =38
Needle = JD Red
Clip position = 3rd
Air screw setting = 2
Slide = #7
Idle = 1900 rpm
Hrs = 4 hours since top end

Conclusions/Results =
Back from a long weekend of riding, the RED needle definitely assist in bottom end grunt and Walt's airboot mod at 3/4 to top in 5th or 6th just powered with no distinct feel of hesitation.
Tried the BLUE needle the the bottom end felt meek compared to the the RED but the top end part was very responsive almost a distinct role reversal from both needles.
Although l wasn't entirely happy with it we got into single trails at an altitude of 800m to 900m, the bike became hard to start and rev's idle increased to 2500rpm but this could be the radiator hose(water pump end) being too close to the pipe.
Aside from that and the top end, any thought's of selling the WR360 have been wiped

I broke down and purchased a new KEIHIN PWK 38MM from Motosportz and happy to get away from the stocker. Where should I start on the jettings?

Year & Bike Model = 2009 WR250
Carb = KEIHIN PWK 38MM
Pipe & Silencer= Stock
Other engine mods = none
Premix ratio & fuel type = 40:1 and 91 octane no alcohol pump gas Motorex oil
Temperature range (deg F) = Missouri ?
Elevation (feet) = actual altitude is 1000 ft.
Main jet =?
Pilot jet = ?
Needle = ?
Clip position = ?
Air screw setting = ?
Slide = stock

I just did the exact same thing. Bike is an 09 wr 250, I was tired of messing with the Mikuni and so I pulled the trigger on a Keihin from Kelly at Motosportz. What a great idea! I installed carb just as it was delivered, if my memory serves me correctly below are the details as received. Impressions: what a huge difference, no more stuttering...no more racing idle...no more random lean symptoms followed by random rich symptoms. After just one ride I am very pleased, hopefully I will be able to report the same after a couple races. The one thing I would like to know is details on routing of the vent hoses. I had trouble with the Mikuni during the last race that included several knee deep water crossings (ie. water in carb, i suspect coming in through a vent hose). I would like to prevent this with the Keihin, has anyone rerouted any of the hoses as a precaution for deep water crossings? If so, which hoses do you reroute and to where?

Year & Bike Model = 2009 WR250
Carb = KEIHIN PWK 38MM
Pipe & Silencer= FMF Gnarly, Turbinecore 2
Other engine mods = none
Premix ratio & fuel type = 40:1 and 93 octane, Klotz premix
Temperature range (deg F) = Indiana...who knows day to day
Elevation (feet) = actual altitude is roughly 600 ft
Main jet =175
Pilot jet = 45
Needle = JD Blue
Clip position = middle
Air screw setting = 1.5 turns
Slide = stock

Year & Bike Model = 2009 WR250
Carb = Mikuni
Pipe & Silencer =Stock
Other engine mods = none
Premix ratio & fuel type = 32:1 Lucas synthetic blend & VP 110
Temperature range (deg F) = 70 degrees F humidity 50%
Elevation (feet) = actual altitude is 1,100 ft. air density altitude is usually between 1500ft and 2500ft in this area but I have seen 3500 ft air in the humid summer.
Main jet =410
Pilot jet = 30
Needle = E16BFY43-74 stock
Clip position = 2nd clip with 1/2 step washer/spacer
Air screw setting = 1 1/8
Slide = stock 4.0

Idles strong with idle screw flush with lock nut. Pulls hard bottom to top, if I changed anything it would get worse not better. I've tried changing all circuits richer and leaner and this is the sweet middle of crisp.

Here comes my settings for my WR 300 2010. I have used the racehead in the winter, but i jet the same without it.Iit was too much with the racehead in the woods, so i removed it for the summer. I also have a Leo Vince silencer, but that doesn´t affect anything.
Sealevel to 300 meters above and around 15-25 degrees Celsius
Keihin PWK 38 AS with slide 7
JD red needle in lowest (leanest clip position
175 main jet
40 pilotjet
Airscrew 2-21/2 turns out depending on temp
The bike runs very clean, don`t spooge at all, rolls very smooth on idle and starts at first kick almost every time. I like to go quite lean in the gnarly stuff as it makes the bike smooth on throttle and doesn´t make me tired. And when i´m tired i can still get a smooth powerdelivery. I don´t think a lot of bottom end power always is good. It´s strong enough anyway! If it´s jetted richer i get a bludder when i open the throttle and then a sudden powerdelivery when it starts to run clean, and as it is now it is very smooth all the way.
Johnny