WR400/426/450 Jetting Database

[Alternative]

Year: 2002

Model (400 - 426 - 450): 426

Cam Timing (WR/YZ): Decomp cam, don't know if it's WR or YZ

Main jet: 168

Pilot Jet: 42

MAJ: 200

PAJ: 75

Leak Jet: NA

Starter Jet: 65

Fuel screw (turns out): ~2 1/2

Needle Model/Clip position: OBEKQ 4th clip

Grey Wire Mod (Y/N): NA (NZ model don't have it to stat with)

TPS Connected (Y/N): Y

Airbox Snorkel/Lid (on or off): off

AIS Removed (Y/N): ?

Airfilter Brand: Stock

Exhaust Brand: Staintune

Average Altitude: 0-1000 ft

Average Temperature: 5-25 deg C (41-77 deg F)

Average Humidity: 60%

Degree of Satisfaction (0-10): 4 (hopefully will be a 10 when I sort out the jetting)

Additional Mods/Comments: BK mod to bring AP squirt down to 1/2 a second (was about 2 seconds). Idles alright, stumbles all over the place at 1/4 - 1/2 throttle (needle I'm guessing, kinda new to this tuning thing, probably gonna get the JD kit), pulls strong at 1/2 - full throttle but a little on the lean side (plug test). Only just bought the bike, need to get this jetting sorted out so I can see what it really can do!

[bvd]

Year: 2005

Model (400 - 426 - 450): 450

Cam Timing (WR/YZ): stock - WR

Main jet: JD - 165

Pilot Jet: stock - 45 (I think)

PAJ: stock - 80

Leak Jet: stock - 50

Starter Jet: - stock - 65

Fuel screw (turns out): zipty - 1 1/4

Needle Model/Clip position: JD - red 4th from the top

Grey Wire Mod (Y/N): YES

TPS Connected (Y/N): YES

Airbox Snorkel/Lid (on or off): OFF

AIS Removed (Y/N): YES

Airfilter Brand: TwinAir

Exhaust Brand: Stock w/ GYTR Performance WR Muffler Insert

Average Altitude: 6000-10000

Average Temperature: 60-80

Average Humidity: DRY

Degree of Satisfaction (0-10): 10 - I LOVE THIS BIKE! ?

Additional Mods/Comments: Suspension re-sprug and re-valved for a 210 lb B Enduro rider, Rekluse clutch w/perch adjuster, 14-49 gearing, DID X-Ring chain and Renthal sprockets, Acerbis 3.3 gal tank...

I love this bike... I tried putting an 06 YZF exhaust cam in it and it just killed the bottom end.....so I don't recommend it...

[ccoates445]

Year:'07 WR450F

Model (400 - 426 - 450): 450

Cam Timing (WR/YZ):WR

Main jet:165

Pilot Jet:45

PAJ:Stock

Leak Jet:40

Starter Jet:Stock

Fuel screw (turns out):ZipTy 1.5 Turns

Needle Model/Clip position: JD Red 4th slot

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 uncorked w/sparky

Average Altitude:1500-5000

Average Temperature:75-100

Average Humidity:under 20%

Degree of Satisfaction (0-10):So far 9, as there is always room to improve. I love this bike.

Additional Mods/Comments:

[Pooley]

Year: 2001

Model (400 - 426 - 450): WR 426

Cam Timing (WR/YZ): WR timed

Main jet: 168

Pilot Jet: 45

PAJ: 100

Leak Jet: NA

Starter Jet: 65

Fuel screw (turns out): 2 turns out

Needle Model/Clip position: JD Red #4

Grey Wire Mod (Y/N): Yes

TPS Connected (Y/N): Yes (not re-adjusted from factory)

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

AIS Removed (Y/N): NA

Airfilter Brand: Twin Air w/ No-Toil Oil

Exhaust Brand: Stock, with GYT-R Insert

Average Altitude: 700ft (Michigan)

Average Temperature: 70-90 F

Average Humidity: 70-90%

Degree of Satisfaction (0-10): 9 (we can always want more can't we?)

Additional Mods/Comments: Additional mods:

Light Blue Wire

O-Ring Mod (WAY better than BK Mod for me)

ACV disabled (which is why I have a 100 PAJ rather than a 75 stock)

Just did the O-ring mod, and it took my degree of satisfaction from a 6 to a 9!! Can't say enough about the difference it made. Almost made it run like an open exhaust.

[JSanfilippo]

Year:2007

Model (400 - 426 - 450):450

Cam Timing (WR/YZ):WR

Main jet:168 (162 stock)

Pilot Jet: 48 (45 stock)

PAJ:Stock

Leak Jet:Stock

Starter Jet:Stock

Fuel screw (turns out):MSR 1.75 out

Needle Model/Clip position:JD red/4th

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:Twin air

Exhaust Brand:'07 YZ header/ White Bros. E2 muffler

Average Altitude:sea level to 6500ft

Average Temperature:55-100 degrees F

Average Humidity: Across the board

Degree of Satisfaction (0-10):So far 12/10!

Shes unleased now. Everything that everybody says about the WR 450f with an aftermarket exhaust is true. I'm super stoked

[snowman02]

Year:2002

Model (400 - 426 - 450):426

Cam Timing (WR/YZ):WR

Main jet:170

Pilot Jet: 45

PAJ:Stock

Leak Jet:N/A

Starter Jet:Stock

Fuel screw (turns out):1.75

Needle Model/Clip position:JD red/5th For Summer 120 degree heat. Winter see below.

Grey Wire Mod (Y/N):Y

TPS Connected (Y/N):Y

Airbox Snorkel/Lid (on or off): Snorkel Out, Lid Modified

AIS Removed (Y/N):N?A

Airfilter Brand:Twin Air

Exhaust Brand:Stock header muffler FMF PowerCore4

Average Altitude:sea level to 2000'

Average Temperature:45-125 degrees F

Average Humidity: 5-100 Percent

Degree of Satisfaction (0-10):So far 10/10.

Additional Mods/Comments:Thick o-ring mod from the JD kit.

Come Winter I will change out to Blue Needle on 3rd clip. And see if rest of jetting will be fine where it is.

[jobfnl]

Year: 07

Model (400 - 426 - 450): 450

Cam Timing (WR/YZ): WR

Main jet: 168

Pilot Jet: 48

PAJ: 110

Leak Jet: 45

Starter Jet:

Fuel screw (turns out): 1.5

Needle Model/Clip position: red/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: uni

Exhaust Brand: gytr 96db performance insert, p/n gyt-5tj93-75-01:

Average Altitude: 2-4000'

Average Temperature: 80

Average Humidity: low

Degree of Satisfaction (0-10): 9.5

Additional Mods/Comments: first I installed Yamaha AIS kit and found it to be a little rich for me. Bought the JD kit and installed per instructions, thick oring mod. very happy with this setup. left the gytr main air jet and leak jet installed.

[suzukipoo]

Year:2007

Model (400 - 426 - 450):450

Cam Timing (WR/YZ):WR/STOCK

Main jet:170

Pilot Jet:48

PAJ:STOCK

Leak Jet:STOCK

Starter Jet:STOCK

Fuel screw (turns out):1.50

Needle Model/Clip position:AIS NEEDLE #3

Grey Wire Mod (Y/N):YES

TPS Connected (Y/N):YES

Airbox Snorkel/Lid (on or off):OFF

AIS Removed (Y/N):YES

Airfilter Brand:TWIN AIR

Exhaust Brand:FMF FACTORY 4.1 SLIP ON

Average Altitude:1200 METERS

Average Temperature:25 CELCIUS

Average Humidity:40-60%

Degree of Satisfaction (0-10):10

Additional Mods/Comments:NOW MY BABY IS ALIVE!!!!

[airbornedog]

Year: 2007

Model (400 - 426 - 450): 450

Cam Timing (WR/YZ): WR

Main jet: 165

Pilot Jet: 45

PAJ:

Leak Jet: 45

Starter Jet:

Fuel screw (turns out): 1.5

Needle Model/Clip position: Red needle 4th 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: Stock

Exhaust Brand: White Brothers E2 slip on

Average Altitude: 0-4000' asl

Average Temperature: 70-90

Average Humidity:

Degree of Satisfaction (0-10): 9

Additional Mods/Comments: This site helped alot for jetting purposes. No bogs, starts first kick.

[Bleeds_Blue]

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.

[jivenene]

Year: 1999

Model (400 - 426 - 450): 400FL

Cam Timing (WR/YZ): YZ

Main jet: 168

Pilot Jet: 45

PAJ1: 75

PAJ2: 90

Main air jet: 200

Leak Jet: N/A?

Starter Jet: 60

Fuel (pilot) screw (turns out): 1.5 (still tuning)

Needle Model/Clip position: OBDTM(stock)/4

Grey Wire Mod (Y/N): Y

TPS Connected (Y/N): Y

Airbox Snorkel/Lid (on or off): OFF

AIS Removed (Y/N): N/A

Airfilter Brand: Stock

Exhaust Brand: stock YZF426

Average Altitude: 0ft

Average Temperature: 80F (27C)

Average Humidity: 70%

Degree of Satisfaction (0-10): 9

Additional Mods/Comments: Also have home made AvNow installed (1/4 and ½ open plates). Mostly stock setup, with ZipTy fuel (pilot) screw. Starts w/o choke on 2nd kick. No hesitation/bog, instant throttle response. Linear power band, no peaks or dips. No afterfire (backfire) after changing clip from position 3 to 4.

[Evad101]

Year: 2008

Model (400 - 426 - 450): 450

Cam Timing (WR/YZ): WR

Main jet: JD 168

Pilot Jet: JD 48

PAJ: YEC AIS 110

Leak Jet: YEC AIS 45

Starter Jet:

Fuel screw (turns out): MSR 2

Needle Model/Clip position: JD red/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: Stock

Exhaust Brand: Stock, unplugged

Average Altitude: SEA - 2000'

Average Temperature: 45-55 (So Far)

Average Humidity: 70%

Degree of Satisfaction (0-10): 8

Additional Mods/Comments: W/ Small JD O-ring MOD - This is a combo of the YEC AIS kit and a JD Jet Kit. Runs great, no bogs, but I only got 27.3 miles until I had to switch to reserve. Will try leaning it out a bit and update.

[lvcta21]

Year: 2007

Model (400 - 426 - 450): 450

Cam Timing (WR/YZ): WR

Main jet: 168

Pilot Jet: 48

PAJ: 70 (stock)

MAJ: 110

Leak Jet: R&D power pump set at approx. 40

Starter Jet: 65 (stock)

Fuel screw (turns out): Zip-Ty 1.5

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

Grey Wire Mod (Y/N): Y

TPS Connected (Y/N): Y

Accel. Pump O-ring MOD (Y/N): Y

Airbox Snorkel/Lid (on or off): Off

AIS Removed (Y/N): Y

Airfilter Brand: Stock

Exhaust Brand: Stock w/GYTR insert

Average Altitude: 800'

Average Temperature: 80

Average Humidity: 70%

Degree of Satisfaction (0-10): 9.5

Additional Mods/Comments: R&D power pump is great for fine tuning the leak jet to get rid of that off-idle bog and just needs slight adjustments for Summer vs. Winter operation!

[kawi380]

Year: 2008

Model (400 - 426 - 450): 450

Cam Timing (WR/YZ): wr

Main jet: 168

Pilot Jet: 45

PAJ: 110

Leak Jet: 50

Starter Jet: 68

Fuel screw (turns out): stock 1.5

Needle Model/Clip position: GYTR AIS 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: stock

Exhaust Brand: stock pea shooter removed

Average Altitude: 4000 to 6000 ft

Average Temperature: mid 50's right now

Average Humidity: 20-30%

Degree of Satisfaction (0-10):9

Additional Mods/Comments: still have a slight hesitation off idle, but have barely done a short break-in ride.

[gilberje]

Year:2000

Model (400 - 426 - 450):400

Cam Timing (WR/YZ):YZ

Main jet:178

Pilot Jet:48

PAJ:75

Leak Jet:

Starter Jet:65

Fuel screw (turns out):1 1/4

Needle Model/Clip position:stk needle, 3rd position

Grey Wire Mod (Y/N):Y

TPS Connected (Y/N):Y

Airbox Snorkel/Lid (on or off):off

AIS Removed (Y/N):N/A

Airfilter Brand:UNI

Exhaust Brand:stk with baffle removed

Average Altitude:1000-4000

Average Temperature:50-70

Average Humidity:

Degree of Satisfaction (0-10):9

Additional Mods/Comments:homemade power now. runs great, no bog, instant response, starts 1-2 kicks everytime

[Island Boy]

Year: 2007

Model (400 - 426 - 450): WR450

Cam Timing (WR/YZ): WR

Main jet: 168

Pilot Jet: 48

Leak Jet: Set at 40 (R&D Power Pump with ALJ)

Starter Jet: 65 (Stock)

Fuel screw (turns out): GYTR Fuel Screw 2 Turns Out (still tuning)

Needle Model/Clip position: JD Red / 4th 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: Uni

Exhaust Brand: Dr. D Full Race

Average Altitude: Sea Level

Average Temperature: 80 - 90 F

Degree of Satisfaction (0-10): Will be testing this weekend

Additional Mods/Comments: R & D stiffer spring installed on AP linkage arm.

[Idaho450]

Model (400 - 426 - 450): 2007 WR450

Timing (WR-YZ): WR

Main jet: 165

Pilot Jet: 45

Fuel screw (turns out): ZipTy - 1.5 out

Needle model/Clip position: JD red 4

Airbox lid (off): snorkel removed

Pipe: Stock header, FMF Q4

air filter: Stock

Altitude where you ride: 2500 - 5,500 ASL

Temperature where you ride: ~50 - 85 degrees.

Degree of satisfaction 9.9

[C-P]

Year: 2007

Model (400 - 426 - 450): 450

Cam Timing (WR/YZ): wr

Main jet: 168

Pilot Jet: 48

All other jets from the GYTR AIS kit installed

Fuel screw (turns out): Zip TY 1.5

Needle Model/Clip position: GYTR AIS 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: stock

Exhaust Brand: stock pea shooter removed

Average Altitude: 0-500ft

Average Temperature: 70-90, but 50 right now

Degree of Satisfaction (0-10):9

Additional Mods/Comments: O-ring'd the AP arm linkage too. No off idle hesitation, a little popping here and there at 1/2 to 3/4 throttle, couple twists would clean it up. Didn't seem to have any related power loss. Have only put on about 40 miles so far. Very happy with overall performance and rideability.

[hackmaster]

Year:2001

Model (400 - 426 - 450):wr426

Cam Timing (WR/YZ):yz

Main jet:168

Pilot Jet:62

PAJ:60

MAJ:200

Leak Jet:stock

Starter Jet:stock

Fuel screw (turns out):2 1/2 turns out

Needle Model/Clip position:jd blue 2nd clip from top

Grey Wire Mod (Y/N):n

TPS Connected (Y/N):y

Airbox Snorkel/Lid (on or off):off

AIS Removed (Y/N):y

Airfilter Brand:twin air

Exhaust Brand:dr.d full stepped system

Average Altitude:1000m above sea level

Average Temperature:20c

Average Humidity:50-70%

Degree of Satisfaction (0-10):10

Additional Mods/Comments:wisco 13.5:1 comp piston, port an polished head,full dr.d exahust system, alot of bling added to carb. these mods made the bike come to life.?

[TWILES]

Re: JETTING D-Base WR400/426/450

Year: 2005

Model (400 - 426 - 450): 450

Cam Timing (WR/YZ): WR

Main jet: 170

Pilot Jet: 48

PAJ: stock

Leak Jet: plugged

Starter Jet: 75

Fuel screw (turns out): Pro Circuit 1.5 - 2

Needle Model/Clip position: Stock 2005 YZ NFLR middle clip (up or down 4)

TPS Connected (Y/N): Yes

Grey Wire Mod (Y/N): Yes

Airbox Snorkel/Lid (On/Off): Off

AIS Removed (Y/N): Yes

Airfilter Brand: UNI

Exhaust Brand: Stock 2005 YZ450

Average Altitude: 350 - 1000

Average Temperature: 75

Average Humidity: 45%

Degree of Satisfaction (0-10): 10

Additional Mods/Comments:

I live in Western KY. This should work in the News Channel 6 viewing area. I'm also using Sunco 110 because I keep getting bad gas from all the gas stations in town. It will rip. I plugged the leak jet with a ball I cut off of a pull-chain from a lamp. Drop it in a screw the leak jet in. It sticks up but does affect anything. I also have the AP set to where when the throttle is wide open, the rod is at the bottom with maybe a sheet of papers thickness between the screw and plastic piece on the AP.