WR400/426/450 Jetting Database

Year: 2006

Model (400 - 426 - 450): WR450

Cam Timing (WR/YZ): WR

Main jet: 168

Pilot Jet: stock

Leak Jet: stock with O-ring mod on linkage

Starter Jet: 65 (Stock)

Fuel screw (turns out): ZIP TY Fuel Screw 1.5 Turns Out (still tuning)

Needle Model/Clip position: JD Red / 5th Position

Grey Wire Mod (Y/N): Y

TPS Connected (Y/N): Y

Airbox Snorkel/Lid (on or off): Off

AIS Removed (Y/N): Y

Airfilter Brand: stock

Exhaust Brand: stock

Average Altitude: 3000_6000ft

Average Temperature: 80 - 90 F

Degree of Satisfaction (0-10): 9

Additional Mods/Comments: a couple of stickers

Year: 2008

Model (400 - 426 - 450): 450

Cam Timing (WR/YZ): WR

Main jet: 168

Pilot Jet: 48

Fuel screw (turns out): Scotts, 1,5 turns out

Needle Model/Clip position: JD Blue 4th Position

Grey Wire Mod (Y/N): y

TPS Connected (Y/N): y

Airbox Snorkel/Lid (on or off): On

AIS Removed (Y/N): n

Airfilter Brand: stock

Exhaust Brand: stock exhaust entire baffel removed

Average Altitude: 0-500ft

Average Temperature: 50-80,

Degree of Satisfaction (0-10):9

Additional Mods/Comments: O-ring'd the AP arm linkage with the thick O ring from the JD Jetting kit. Imported the kit from the US (live in the UK) Was sceptical how much this kit would help but now that I have installed it I am absolutely blown away. It's like riding a different bike. Can't keep the front wheel down, starts so easily, is smoother and tons more power. The JD jetting kit is an awesome product!!

Year: 2008

Model (400 - 426 - 450): 450

Cam Timing (WR/YZ): WR

Main jet: 170

Main Air Jet: 110

Pilot Jet: 48

Pilot Air Jet: 70

Leak Jet: 45

Starter Jet: 65

Fuel screw (turns out): Zip Ty 1-3/4

Needle Model/Clip position: GDDUQ / 4

Grey Wire Mod (Y/N): N/A in Sweden

TPS Connected (Y/N): Y

Air box Snorkel/Lid (on or off): Off / Off

AIS Removed (Y/N): N

Air filter Brand: Stock

Exhaust Brand: Stock

Average Altitude: 0-500ft / 0-150m

Average Temperature: 68-77f / 20-25c (In summer)

Average Humidity: 50-80%

Degree of Satisfaction (0-10): 9 (still to improve the exhaust)

Additional Mods/Comments: Pee shouter removed. O-ring at the AP arm linkage (O-ring mod removed the off-idle bog completely).

Year: 1999

Model (400 - 426 - 450): WR400F EU-version

Cam Timing (WR/YZ): WR

Main jet: 172

Pilot Jet: 45

PAJ: Stock

Leak Jet: There is no such thing

Starter Jet: 60

Fuel screw (turns out): 2½

Needle Model/Clip position: 6th

Accelerator pump diaphragm: "Yamaha -19" (0.75sec duration)

Grey Wire Mod (Y/N): No need to. EU version

TPS Connected (Y/N): Yes

Airbox Snorkel/Lid (on or off): Lid off

Airfilter Brand: TwinAir

Exhaust Brand: White Brothers E-series

Average Altitude: 0- 1600 feet

Average Temperature: 60-85

Degree of Satisfaction (0-10): 10

Year: 2006

Model (400 - 426 - 450): WR450

Cam Timing (WR/YZ): WR

Main jet: 158

Pilot Jet: stock

Leak Jet: #60

Starter Jet: 65 (Stock)

Fuel screw (turns out): ZIP TY Fuel Screw 1.5 Turns Out

Needle Model/Clip position: YZ std needle '05 3rd from top

Grey Wire Mod (Y/N): Y

TPS Connected (Y/N): Y

Airbox Snorkel/Lid (on or off): Off

AIS Removed (Y/N): Y

Airfilter Brand: No toil

Exhaust Brand: FMF Q4

Average Altitude: 5000_9000ft

Average Temperature: 70 - 85 F

Degree of Satisfaction (0-10): 9

Additional Mods/Comments: I have been running red #4 in cooler temps but it was still to rich. I just put in the #60 leak jet and have eliminated the initial throttle hesitation. I will probably changing the main jet depending on temp. I have done the o-ring mod too. If I don't find this set up working I will be pulling out the JD needles and go with stock YZ needle from here on out. I also have a quickshot 2 on the carb. I'm no longer using JD needles.

Year: 2006

Model (400 - 426 - 450): WR450

Cam Timing (WR/YZ): YZ

Main jet: 165

Pilot Jet: 40 (ACV is disabled)

Leak Jet: #71 (#50 drilled out)

Starter Jet: 72

Pilot Air Jet: 100

Fuel screw (turns out): ZIP TY Fuel Screw 1.5 Turns Out

Needle Model/Clip position: NFPR - 4

Grey Wire Mod (Y/N): Y

Blue/White Wire Mod (Y/N): Y - starts fairly fast even with YZ exhaust cam

TPS Connected (Y/N): Y

Airbox Snorkel/Lid (on or off): Off

AIS Removed (Y/N): Y

Airfilter Brand: Twin Air

Exhaust Brand: FMF Powercore 4, Stock headpipe

Average Altitude: 3000 - 9000ft

Average Temperature: 60 - 90 F

Degree of Satisfaction (0-10): 9.5

Additional Mods/Comments: Red Beard AP mod (diaphram stud ground off, linkage wired - I got tired of replacing O-rings and this works better). Powernow and Scary Fast Powershot AP pump cover. No hesitation or bog. I am on the rich side throughout but the Powernow, which does help bottom end, pulls more more gas.

Year: 2008

Model (400 - 426 - 450): 450

Cam Timing (WR/YZ): WR

Main jet: 152 (yes, a 152!)

Pilot Jet: STOCK

PAJ: STOCK

Leak Jet: STOCK

Starter Jet: STOCK

Fuel screw (turns out): 2

Needle Model/Clip position: GYTR-AIS REM. KIT "MYSTERY NEEDLE", 2ND FROM THE TOP.

Grey Wire Mod (Y/N): Y

TPS Connected (Y/N): Y

Airbox Snorkel/Lid (on or off): OFF

AIS Removed (Y/N): Y

Airfilter Brand: STOCK

Exhaust Brand: FMF POWERCORE 4

Average Altitude: 5000-14,000ft

Average Temperature: 50-80F

Average Humidity: Pretty darn DRY!

Degree of Satisfaction (0-10): 9.5

Additional Mods/Comments: This bike runs STRONG! NO STUTTER or any overheating from 5000-11,000ft, and starts instantly. Above 11,000ft some of the stutter starts to come back, but it's minimal, and it still starts right up. No bog or hesitation anywhere in my altitude range!:thumbsup:

Year: 2006

Model (400 - 426 - 450): WR450

Cam Timing (WR/YZ): WR

Main jet: 165

Pilot Jet: 48

Leak Jet: 40

Starter Jet: 70

Pilot Air Jet: 100

Fuel screw (turns out): PRO CIRCUIT 2.25 TURNS OUT

Needle Model/Clip position: GYTR AIS/5TH

Grey Wire Mod (Y/N): Y

TPS Connected (Y/N): Y

Airbox Snorkel/Lid (on or off): Off

AIS Removed (Y/N): Y

Airfilter Brand: UNI FILTER

Exhaust Brand: AKRAPOVIC, Stock headpipe

Average Altitude: 2700 - 4000ft

Average Temperature: 60 - 90 F

Degree of Satisfaction (0-10): 9

Additional Mods/Comments: AP mod. Quickshot 2. No hesitation or bog.

Year:2000

Model (400 - 426 - 450):400

Cam Timing (WR/YZ):YZ

Main jet:168

Pilot Jet:48

PAJ:stock

Leak Jet:n/a

Starter Jet:stock

Fuel screw (turns out):1 1/2

Needle Model/Clip position:JD red 4th

Grey Wire Mod (Y/N):Canadian model so no and yes

TPS Connected (Y/N):Y

Airbox Snorkel/Lid (on or off):Off

AIS Removed (Y/N):n/a

Airfilter Brand: not sure

Exhaust Brand:White brother R series

Average Altitude:600-2000

Average Temperature:55-95

Average Humidity:60-80%

Degree of Satisfaction (0-10):8

Additional Mods/Comments:Still fine tuning but it runs very good as is starts easy and no bog. O-ring and BK mod done.

Year: 2006

Model (400 - 426 - 450): 450

Cam Timing (WR/YZ): WR

Main jet: 168

Pilot Jet: 48

PAJ: stock

Leak Jet: stock

Starter Jet: stock

Fuel screw (turns out): 1.5-2

Needle Model/Clip position: NVCQ (yfz450 needle) 4th clip

Grey Wire Mod (Y/N): Y

TPS Connected (Y/N): Y

Airbox Snorkel/Lid (on or off): off w/holes in lid

AIS Removed (Y/N): Y

Airfilter Brand: K&N

Exhaust Brand: FMF Factory 4.1 Carbon

Average Altitude: 800ft.

Average Temperature: 50-90

Average Humidity: 60-100%

Degree of Satisfaction (0-10): 8.9

Additional Mods/Comments: o-ring mod done. e-starts are quick hot or cold. 1 kick hot or cold. michigan temperatures range throughout the day so i make adjustments to the fuel screw daily

Model: 2006 WR450F

Cam Timing: WR (stock)

Main Jet: 168 (165 is stock)

Pilot Jet: 48 (45 is stock)

Fuel screw: GYTR - 2 out (about)

Needle model/Clip position: 4th pos on needle from GYTR AIS kit

Starter Jet: 65 (stock)

Leak Jet: 40 (50 is stock)

Airbox lid (on or off): snorkel removed, holes in side of box

AIS: GYTR AIS removal kit

Grey Wire Mod (Y/N): YES

Pipe: FMF Q w/ S.A.

Air filter: UNI Multi-Stage

Altitude where you ride: Sea level to 4000

Temperature where you ride: Varies, mostly 70s-80s(Jawbone)

Degree of Jetting satisfaction: Need to test, will report. :p

Model: 2006 WR450F

Cam Timing: WR (stock)

Main Jet: 170 (165 is stock)

Pilot Jet: 48 (45 is stock)

Fuel screw: GYTR - 1.75 out (about)

Needle model/Clip position: 4th pos on needle from GYTR AIS kit

Starter Jet: 65 (stock)

Leak Jet: 40 (50 is stock)

Airbox lid (on or off): snorkel removed, holes in side of box

AIS: GYTR AIS removal kit

Grey Wire Mod (Y/N): YES

Pipe: White Bros E2

Air filter: UNI Multi-Stage

Additional Mods: PowerNow

Altitude where you ride: Sea level to 4000

Temperature where you ride: Varies, mostly 70s-80s(Jawbone)

Degree of Jetting satisfaction: Rips.

Year: 2008

Model 2008 WR

Cam Timing (WR/YZ):WR

Main jet:168

Pilot Jet:48

PAJ:110

Leak Jet:45

Starter Jet:65

Fuel screw (turns out):1.75

Needle Model/Clip position:GYTR 4th

Grey Wire Mod (Y/N):Y

TPS Connected (Y/N):

Airbox Snorkel/Lid (on or off):OFF

AIS Removed (Y/N):Y

Airfilter Brand:STOCK

Exhaust Brand:STOCK PMB INSERT

Average Altitude:0-7000FT

Average Temperature:50-90

Average Humidity:

Degree of Satisfaction (0-10):9

Additional Mods/Comments:AIS KIT a little rich still fine tuning runs fine 2nd time on it .

Year: 2008

Model (400 - 426 - 450): 450

Cam Timing (WR/YZ): WR

Main jet: 170

Main Air Jet: 110 (GYTR-AIS)

Pilot Jet: 48

Pilot Air Jet: 80

Leak Jet: 50

Starter Jet: 65

Fuel screw (turns out): Zip Ty 1-1/2 (still tuning)

Needle Model/Clip position: JD red / 4th clip

Grey Wire Mod (Y/N): Y

TPS Connected (Y/N): Y

Air box Snorkel/Lid : Removed

O-ring mode: Done

AIS Removed (Y/N): Y

Air filter Brand: Twin Air

Exhaust Brand: FMF Factory 4.1 complete (open)

Average Altitude: 0-500ft

Average Temperature: 60-90f

Average Humidity: 50-80%

Degree of Satisfaction (0-10): 9

Additional Mods/Comments: I've got before the 175main - 50 Pilot. The bike before accelarates immediately and make some backfire. Now with the 170/48 runs more smoothly.

Year: 2007

Model (400 - 426 - 450): 450

Cam Timing (WR/YZ): WR

Main jet: 165

Pilot Jet: 45

PAJ:

Leak Jet:

Starter Jet:

Fuel screw (turns out): 1 1/2

Needle Model/Clip position: 4

Grey Wire Mod (Y/N): Y

TPS Connected (Y/N): Y

Airbox Snorkel/Lid (on or off): OFF

AIS Removed (Y/N): Y

Airfilter Brand:NO-TOIL

Exhaust Brand: STOCK

Average Altitude: 4-9000

Average Temperature: 80?

Average Humidity: DRY

Year: 2009

Model (400 - 426 - 450): 450

Cam Timing (WR/YZ): WR

Main jet: 165

Pilot Jet: 48

PAJ: Stock

Leak Jet: 45

Starter Jet: Stock (don't know what size it is)

Fuel screw (turns out): 1.5

Needle Model/Clip position: JD Red needle 5th clip

Grey Wire Mod (Y/N): Y

TPS Connected (Y/N): Y

Airbox Snorkel/Lid (on or off): off

AIS Removed (Y/N): Y

Airfilter Brand: Stock

Exhaust Brand: Stock (removed the little pee pee from the exhaust)

Average Altitude: 800-1600

Average Temperature: 75-85F

Average Humidity: no idea

Degree of Satisfaction (0-10): 10 and its scary powerfull

Additional Mods/Comments: Swing arm graphics.. i think they added like 3 horsepower

Year: 2007

Model : 450

Cam Timing (WR/YZ): WR

Main jet: 168

Main Air Jet: 70

Pilot Jet: 42

Leak Jet: 45

Starter Jet: 65

Fuel screw (turns out): 2 1/8

Needle Model/Clip position: JD red / 3rd clip pos.

Grey Wire Mod (Y/N): Y

TPS Connected (Y/N): Y

Air box Snorkel/Lid : Removed

O-ring mode: JD THICK

AIS Removed (Y/N): Y

Air filter Brand: TWIN AIR

Exhaust Brand: STOCK OPENED UP

Average Altitude: 300-1000ft

Average Temperature: 55-70f CURRENT

Average Humidity: 40-80%

Degree of Satisfaction (0-10): 9

Edited by wilb67

Year: 2008 AUSTRALIAN

Model : 450

Cam Timing (WR/YZ): WR

Main jet: 168

Main Air Jet:STD

Pilot Jet: 45

Leak Jet: STD

Starter Jet: STD

Fuel screw (turns out): 1 3/4

Needle Model/Clip position: GDDSQ / 4 clip

Grey Wire Mod (Y/N): Y

TPS Connected (Y/N): Y

Air box Snorkel/Lid : Removed

O-ring mode: NONE

AIS Removed (Y/N): NONE

Air filter Brand: Twin Air

Exhaust Brand: GYTR STD HEADER

Average Altitude: 0-1000ft

Average Temperature: 20-40 DEG Celcius

Average Humidity: 20-70%

Degree of Satisfaction (0-10): 9

still fine tuning would like a yz header to shift mid range a little higher:thumbsup:

Edited by DAVE BT

Year: 2007

Model (400 - 426 - 450): 450

Cam Timing (WR/YZ): Hot Cams Stage 1

Main jet: 170

Pilot Jet: 48

PAJ: 110

Starter Jet: STD

Fuel screw (turns out): 2 turns out

Needle Model/Clip position: JD Red 5th clip

Grey Wire Mod (Y/N): Y

TPS Connected (Y/N): Y

Airbox Snorkel/Lid (on or off): OFF

AIS Removed (Y/N): Y

Airfilter Brand: GYTR

Exhaust Brand: Lexx MXE silencer with pro circuit head pipe

Average Altitude: 500-2000

Average Temperature: 50-95

Average Humidity: 80%

Degree of Satisfaction (0-10): 9

Additional Mods/Comments: Bike pulls hard through the whole power curve. Still a little studder at steady throtle but I think its the normal studder for the bike.

Year:2002

Model: 426

Cam Timing: 2003 YZ 450 CAM

Main jet:170

Pilot Jet:45

PAJ:STOCK

Leak Jet:STOCK

Starter Jet:STOCK

Fuel screw (turns out):2

Needle Model/Clip position:3 (Needle from YFZ 450 quad)

Grey Wire Mod (Y/N): Y

TPS Connected (Y/N): Y

Airbox Snorkel/Lid (on or off): OFF

AIS Removed (Y/N):N

Airfilter Brand:?

Exhaust Brand: Leo Vince full system

Average Altitude:Sealevel ( California)

Average Temperature: (60-90)

Average Humidity: 60-70

Degree of Satisfaction (0-10): 8

Additional Mods/Comments:

I just added the needle and adjusted the acc pump, it ran great before with some off idle studder, hopefully that is gone now.

Year: 2010

Model (400 - 426 - 450):

Cam Timing (WR/YZ):

Main jet: 168

MAJ: 178 (#54 drill)

Pilot Jet:42

PAJ:84 (#66 drill)

Leak Jet: R&D adjustable

Starter Jet:65

Fuel screw (turns out):2 1/4

Needle Model/Clip position: **DVR-#4

Grey Wire Mod (Y/N):

TPS Connected (Y/N):

Airbox Snorkel/Lid (on or off):

AIS Removed (Y/N):

Airfilter Brand: Moto Air

Exhaust Brand: 2008 YZ450F mechanically baffled

Average Altitude:0-3000'

Average Temperature: 65-75F

Average Humidity:75%

Degree of Satisfaction (0-10):9

Additional Mods/Comments:

TPS voltage: 0.70v

Float Height: 9mm

Squirt length: 15"

O'ring mod

2nd gen BK style mod

R&D AP link spring

enlarged AP feeder orifice

Will do 60 miles before hitting reserve in GNCC style conditions

p.s. IMHO, this thread is pretty much useless unless PAJ, MAJ and float height are made compulsory inputs, the rest of the jetting hangs off these criteria. If the tuner doesn't know these values, their input is questionable anyway.

Edited by Nutty Professor

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