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WR400/426/450 Modification Database

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Okay kids, here we go again. Since a lot of folks want to know what others have screwed, glued, and tattoed to there bikes to make it more comfortable, personable or unique, I've decided to put together a Modification Database. I'm going to run it just like the Jetting Database. Please list your modifications using the following template:


Engine: (Cams, plugs, Filters, AIS kit, etc.)

Carb: (Quickshot, Fuel Screw, Jetting Kit, Modifications, Replacement, etc.)

Exhaust: (Can, Header, Mid-pipe, Modifications, etc.)

Fluids: (Oil, Coolant, Brake Fluid)

Suspension: (Springs, Fluids, Modifications, Replacements, etc.)

Chassis: (Bars, Grips, Triple Clamps, Levers, Pegs, Brakes, Lines, Modifications, etc.)

Protection: (Skid Plate, Bark Busters, Pipe Guard, Caliper/Rotor Guards, etc.)

Tires/Wheels: (Rims, Spokes, Hubs, Tubes, Axles, etc.)

Driveline: (Sprockets, Chain)

Electrical: (GPS, Computers, Dual-Sport Kits, etc.)

Cosmetic: (Graphics, Plastic, Seat Covers, etc.)



In an effort to keep the database streamlined and uncluttered, conversational posts will be deleted. If you post your settings, please try to remember to keep them updated as you change your bike's setup so the information stays current. I'll keep the thread sticky for a while so we can get a good cross section of bikes. Thanks for your help 👍 ...SC

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Model/Year: 2005 WR450

Engine: TT AIS Kit, Twin Air Filter, Ready Racing SS Oil Filter, Rekluse Z-Start w/ Perch Adjuster

Carb: JD Kit, Quickshot, PowerNow, Zip-Ty Fuel Screw, AP Linkage w/ O-ring mod, ASV Underbar Hot Start Lever on right side

Exhaust: FMF Powerbomb SX, Dr. D can

Fluids: Amsoil, Maxima Coolanol, 7.5# Amsoil Shock Therapy

Suspension: .48 RT Fork Springs, 5.8 RT Shock Spring, EE Fork Bleeders, Shock Sox

Chassis: ProTaper Contours, ProGrip grips, Scotts Upper Triple w/ SUB Mount & Damper, Fastway F2 Pegs

Protection: Utah Sport Skidplate, Cycra ProBends, E-Line CF Pipe Guard, Works Connection Frame & Caliper Guard, Moose Sharkfin

Tires/Wheels: OEM Wheels w/ Maxxis SI Front/IT Rear, Bridgestone UHD tubes, EE Axle Blocks

Driveline: Ironman Sprockets 13/49 Ratio, OEM Chain

Electrical: Lights Removed, Neutral Switch removed/replaced w/ Dr. D. Site Glass, SenDec Tach/Hourmeter

Cosmetic: AMR Racing T-Bomb Graphics, YZ Rear Fender, YZ Front Number Plate

Miscellaneous: Acerbis 3.3 Tank, Subframe mount for sand flag, Dirt-Bike-Gear rear fender bag

Comments: This is my 3rd can and the best so far. Prior to, I had the FMF Q2 and Ti PowerCore.

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Model/Year: 2006 WR450

Engine: stock with the mods

Carb: quickshot, jd kit (forgot what jets)

Exhaust: stock, only 1 baffle left

Fluids: motul

Suspension: stock

Chassis: scotts stabilizer, fat bars, asv's, pro moto billet rack

Protection: gtyr skid, Tripple clamp mounted bark busters

Tires/Wheels: maxxis it desert


Electrical: plated d/s

Cosmetic: battle scars

Miscellaneous: Have the 6.6 gal acerbes tank


John in Vegas

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2006 WR450

Engine: Stock, with AIS removed.

Carb: OEM, jetted, Fuel screw.

Exhaust: OEM Headpipe, FMF Ti Powercore.

Fluids: Rotella-T 5-40, others OEM.

Suspension: Fr. Factory Connection .48 springs, +10cc oil, Aircell Sub Tanks (love 'em!), Rr. Factory Connection 5.6 spring.

Chassis: Applied Racing Tripple clamp w/Renthal Fat Bars, Spyder Grips, ASV levers.

Protection: Devol Frame guards.

Tires: Maxxis SI front, Maxxis IT rear.

Driveline: OEM

Electrical: OEM

Cosmetics: OEM graphics with Attack Graphics pre-printed backgrounds.

Comments: Best modifications... Investing the time and money to get the suspension right...

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Model/Year: '07 WR 450f

Engine: Stock internals, twin air filter, open airbox, AIS block off

Carb: JD jetting, MSR fuel screw, o-ring mod

Exhaust: Stock header & muffler, PMB performance insert

Fluids: Motor oil: Rotella T 15w-40 (soon to be 5w-40 synth), Coolant: 25/75 prestone/distilled water w/ water wetter, stock brake fluid

Suspension: Stock

Chassis: Stock

Protection: moose skid plate, MSR handguards, unabiker rad guards

Tires/Wheels: Stock wheels, Dunlop 120/90-18 D952 rear tire

Driveline: Stock

Electrical: Aftermarket (more better) kill switch

Cosmetic: Stock

Miscellaneous: Scratches and scuffs

Comments: Its relatively stock, but even in this configuration it kicks ass! :busted: Probably going to get a Dr.D full system, IMS natural 3.1 gal tank, White plastics, Doug Henry graphics kit, black seat, and gold hubs/black wheels in the future 👍

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Model/Year: 2005 WR450F

Engine: (TT AIS kit)

Carb: (R&D Lightning, Tusk Fuel Screw, JD Jetting Kit)

Exhaust: (FMF Powercore4 with Quiet Insert)

Fluids: (Engine Ice Coolant)

Suspension: (5.6 Rear Spring, Shimmed .46 front springs, 7.5 Weight Oil)

Chassis: (Pro-taper Woods High Bars, Spider Grips, Tusk Big Bar Adapters/Risers)

Protection: (Devol Skid Plate, Cycra Pro-bend Triple Clamp Mounted Bark Busters)

Tires/Wheels: (Maxxis Desert Hard Terrain Rear, Maxxis IT Front)

Driveline: (14/50 Gearing Steel Primary Drive Sprockets, Moose O-ring Chain)

Electrical: (None)

Cosmetic: (Stripped off Stock graphics, Vinyl Tiki and Sea turtle)


Comments: The JD kit and the suspension mods are the best bang for your buck.

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Model/Year: WR450F 2004

Engine: 24oz flywheel (20% lighter than oem)

Carb: Quickshot, Zip-Ty Fuel Screw, JD Jetting Kit,

Exhaust: Pro-Tec Muffler (slipped on oem header)

Fluids: Elf XT oil

Suspension: Race Tech Springs front (up one stiffness from oem) and rear (up two stiffness from oem), ELF Oil, Race Tech Goldvalves front and rear

Chassis: ProTaper Bar, MSR Shorty Clutch Lever

Protection: GYTR-Aluminium handguards

Tires/Wheels: Heavy Duty Tubes (14-15psi never flat)

Driveline: 50T Rear Sprocket, DID X-Ring Chain

Electrical: Magellan eXplorist 600 GPS, Trailtech Vapor Computer, Trailtech 8" Race HID Light, Trailtech Helmet light, Trailtech 100W Stator, Trailtech 24 oz Flywheel (more powerful magnets).

Cosmetic: CE-Moto Graphics,

Miscellaneous: IMS 13 Liter tank, NOMAD rear fender tank 4 liter

Comments: Racetech suspension was the best handling upgrade and the Trailtech light solution prolongs the riding season

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2002 WR426F:

Engine: Auto-decompression exhaust cam, NGK Iridium spark plug

Carb: JD Jetting kit, BK mod

Exhaust: Staintune can

Fluids: 10W40 API SG rated semi-synthetic motorcycle oil

Suspension: Stock

Chassis: Renthal bars, EBC 320 mm contour front rotor, SS braided front brake line

Protection: Bark Buster hand guards

Tires/Wheels: 17" wheels off Suzuki GSF250 Bandit powdercoated blue, Michelin Pilot Activ tyres 110/70 front, 150/70 rear

Driveline: RK XW-ring chain, 16/44 gearing

Electrical: Trail Tech Vapor, stock dual-sport kit

Cosmetic: Black plastics, Factory Effex Evo 5 graphics kit

Miscellaneous: NZ:nz: Plated

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Model/Year: 1998 WR400

Engine: 03 auto decompress cam, 05 coil on plug, TI headpipe, Rekluse Z-Start w/ Perch Adjuster

Carb: Edelbrock Carb, #7 needle

Exhaust: TI headpipe, stock WR muffler with PMB end cap

Fluids: Rotella T 10-30

Suspension: Stock springs front and rear, clickers set to liking

Chassis: ProTaper bars, BRP Upper Triple w/ SUB Mount & Scotts Damper, aluminun sub frame, TM Designworks chain guide and swingarm slider,

Protection: Cycra ProBends, Works Connection Frame & Caliper Guard, BRP Sharkfin

Tires/Wheels: OEM Wheels w/ Maxxis SI Front/IT Rear, UHD tubes,

Driveline: Renthal Twinring rear Sprocket 14/49 Ratio, OEM Chain

Electrical: Home built dual sport kit with HID headlight, LED tail and turn signals. Sealed lead/acid battery. Garmin GPS V, Endurance odo/spedo.

Cosmetic: e-line graphics kit. Guts tall seat foam and cover

Miscellaneous: Calif. Street Legal WR, Stock 3.2 tank, Rear fender bag with complete tool kit.

Comments: This bike has a zilliion miles of trail riding, racing and dual sport rides on it with no motor work (except for removing head to remove carb slide parts that came undone). Up and down Baja, Copper Canyon and everywhere in between.

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Model/Year:2007 WR 450

Engine: AIS remove ,Uni Filter, Snorkel removed, Crancase breather rerouted and "T"d

Carb: TPS adjusted, Throttle stop cut, Quickshot, Fuel Screw, Jetting Kit, ACV flipped Vent lines "T'd, AP linkage O-ringed, Power Nows (both)

Exhaust: Modified Stock muffler, Peashooter replace by homebuilt 40 mm tailpipe https://thumpertalk.com/forum/sho...d.php?t=349760

Fluids: Opti-4 oil, Water Wetter coolant mix

Suspension:Pro-Action revalve with springs to match my heavy butt, Fork gaitors and seal savers on forks, shock sock, grease zerks installed on swingarm pivots and U-linkage, chain adjuster bolts coated with never seize compound

Chassis: IMS 3.1 gal tank, '06 WR fuel petcock,YZ shrouds, Renthal kevlar grips, Bike Bonz bar clamps, Hammerhead shifter (+5) Brake snake, Ride Eng. hot start

Protection: Cycra Pro bark busters w/sheilds, Cycra front diask guard, Devol Rear disk guard, Utah sport cycle skid plate modified,Works Connection rear caliper guard, Flatland racing rad guards

Tires/Wheels: Bridgestone UHD tubes, Pirelli Scorpion Pro front , Maxxis IT rear

Driveline: Renthal front sprocket 14, sunstar rear 51 DID X-ring chain

Electrical: Blue wire mod, Grey wire mod, Neutral switch removed, Garmin 60cs, Vortex X-10 CDI

Cosmetic: Seitzco Motosports graphics

Miscellaneous:Forks slid up 10mm in clamps

Comments: I went up one tooth on the rear sprocket to cover up what I thought was a weak spot in the 450's low end over my old 426's tractor like power off the bottom.

WR Dave.

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Model/Year:2001 WR426

Engine: Luke's Racing 444 kit w/13.5:1 piston, Hot Cams Intake and Exhaust (autodecomp), Porting by Eric Gorr,

Carb: Quickshot, Zip Ty Fuel Screw, JD Jet Kit, Power Now, ACV blocked, Twin Air filter and that sexy billet cage, added some holes with Uni breathers

Exhaust: Stock head pipe, YZF mid pipe and can, Pro Moto Billet End Cap and Quiet Insert

Fluids: Rotella T, Coolanol with waterwhetter

Suspension: ESP on both ends

Chassis: Renthal FatBars, Spider Grips, Applied Top Clamp, MSR Levers, Moose Racing wide pegs, Ride Engineering SS Brake lines (both ends), Billett brake clevis (rear lever), EBC "MX-S" brake pads stock rotors

Protection: Utah Sport Cycle Skid Plate, Cycra Bark Busters with Triple Clamp Mounts, DeVol Radiator Guards, PMB Shark Fin

Tires/Wheels: Stock wheels, Anderson Automatics wheel spacers (YZF on the front to eliminate the odo drive), Maxxis Desert IT rear and ST front

Driveline: AFAM sprockets, RK O-Ring chain, Fredette Chain Guide, front sprocket is 15T

Electrical: Acerbis DHH heatlight w/55w spot and flood bulbs, Baja Designs LED tail/brake light, K&S Flushmount V turn signals, 1200mAh battery (in the airbox...Li-Ion coming soon), Trail Tech Regulator/rectumfinder, Garmin 60c hardwires on RAM mount, Trail Tech Endurance computer, gray wire disconnected, lighting coil floated

Cosmetic: White plastics w/blue strobe graphics, Complete Seat YZF seat

Miscellaneous: IMS 3.4 gal tank, Moose Racing fender bag and rear fender tool bag, Folding rear view mirror...oh, and I almost forgot...a California Plate hanging on the back fender.

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Model/Year:2005 WR450F

Engine: AIS Removed. GYTR clutch casing

Carb: Zip Ty Fuel Screw, Twin Air filter

Exhaust: Stock head pipe, GYTR Oval end pipe

Fluids: Motul 300V

Suspension: 5kg rear, 0.42kg front + ATF grade fluid, Ballards seal savers.

Chassis: "Braking" front wave disc 270mm, stock pads, Renthal FatBars, Scott Grips, GYTR flexi front brake lever.

Protection: WC Skid Plate, Acerbis Handguards, WC Radiator Guards, WC Frame protectors

Tires/Wheels: Stock wheels, Ballards speedo eliminator, Bridgestone M601 / M602

Driveline: Supersprox 13/50, RK Gold O-Ring chain,GYTR Carbon Fibre Chain Guide.

Electrical: Trailtech Endurance, Perspex headlight protector

Cosmetic: Standard


Comments: Had some drama with the jetting and still not fully sorted in that department, but getting there. Suspension is very dissapointing, even after changing front and rear spring rates to best suit. I hear what you you guy's are saying about a suspension rebuild being the best bang for the buck..........

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Model/Year: 2003 WR450F

Engine: HotCams Intake and Exhaust, YZ Timing, Ceramic/Moly Coated Piston (Wiseco 13.5), Ceramic Coated Combustion Chamber and Head Pipe, All hoses are T'd and re-routed.

Carb: Zip Ty Fuel Screw, Uni filter.

Exhaust: Power Bomb, FMF Q2 with the Spark Arrestor.

Fluids: Bel-Ray Thumper 5w-30, Engine Ice.

Suspension: Revalved by BBRP.

Chassis: Applied Top Clamp, ProTaper Bars, White Knuckle Grips, ASV Levers.

Protection: Devol Skid Plate, Acerbis Handguards, Devol Radiator Guards, Devol Frame protectors

Tires/Wheels: Stock wheels, Maxxis IT.

Drivetrain: Turner Ultralite 12/49, DID O-Ring chain, Rekluse Clutch.

Electrical: LED Taillight.

Cosmetic: One Industries WR, UFO Plastics

Miscellaneous: All the free mods done.

Comments: Ceramic coatings are the way to go. The beast runs ALOT cooler. :banghead:

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Model/Year: 2007 WR450

Engine: No-AIS, Twin air filter, opened up air-box, stock engine

Carb: Fuel Screw, jetted for pipe, R and D Accelerator pump cover. YZ throttle screw

Exhaust: GYTR insert, first baffle removed.

Fluids: All replaced regulary, using various fluids.

Suspension: Stock springs, stealth valves

Chassis: Reikon Bars, magura Jack clutch system, goodrigde braided brake line, solid rear disk, pro-grip grips, sunline gear lever,

Protection: Barkbusters with tripple clamp mounts, radiator guards, bash plate. Hyde Frame guards.

Tires/Wheels: UHD tubes, bridgstone M201, M404.

Driveline: Still stock

Electrical: trailteck computer, removed all blinkers, switchblocks and all adr equipment, acerbis rear led light

Cosmetic: FX graphics


Comments: Hydraulic clutch single best mod!! Closly followed by tyres.

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Model/Year: 2000 WR400

Engine: '03 450 auto-decomp exhaust cam, yz timing, uni air filter, air box modified, gray wire switch to change timing

Carb: homemade power now

Exhaust: FMF powerbomb, stk exhaust with baffle removed

Fluids: all amsoil

Suspension: stk, clickers set to terrian

Chassis: Pro taper bars and grips, ASV levers

Protection: Devol radiator guards, homemade heat shield for powerbomb, moose bark busters

Tires/Wheels: stk rims and hubs, pirelli mt44 front, mt16 rear

Driveline: sunline sprockets, 14/50, DID x-ring chain

Electrical: trail-tech vapor

Cosmetic: YZ tank, seat, and fenders

Comments: runs great, reliable with plenty of power!

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Model/Year: 2000 WR400

Engine: '03 450 auto-decomp exhaust cam, air box modified, gray wire disconnected, throttle stop cut.

Carb: Needs To Be Jetted

Exhaust: stock exhaust with GYTR performance insert

Fluids: nothing special

Suspension: Race Tech fork springs for my weight & YZ handling. Forks dropped 10 mm for SuperMoto.

Chassis: Pro taper bars and grips, Moose levers

Protection: Acerbis Rally Pro handguards. SuperMoto Engineering Axle & Bar Sliders. UFO Peg Sliders. I Pull Out.


-SuperMoto: 17 inch Excel wheel, Talon Hubs w/ Michelin Pilot Power tires (120 ft. 150 rr.)

- Dirt: stock rims and hubs, pirelli mt44 front, MX-Xtra rear


- Supermoto: 15/44. DID X-Ring Chain

- Dirt: 13/50. DID X-Ring Chain (the same chain)

Electrical: TrailTech Vapor computer, TrailTech regulator/rectifier. TrailTech battery. Stator Floated. Acerbis Cyclops headlight. K&S light/turn/kill/horn switch. Brake light pressure switch. LED signals in back, bulb in front. Horn.

Cosmetic: Clarke 3.4 gallon YZ tank, SDG gripper YZ seat (more function than cosmetics). Acerbis SuperMoto ft. fender.

Comments: Runs well considering I've never touched a jet in it though I'd like to change that soon to smooth it out and kill the deceleration pop. In SuperMoto trim, it will do just under 100 mph and will cruise @ 75 mph without rapping out the engine.

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Model/Year: 2000 WR 400

Engine: Hot Cams exhaust and intake cam, big bore kit, yz timing

Carb: Stock carb with fuel screw and jetting mods

Exhaust: FMF powerbomb header with a large dent, FMF Q4 muffler

Fluids: Chevron Delo 400 15w-40 or Valvoline Premium Blue 15w-40 for oil, stock brake and coolant

Suspension: front and rear shocks revalved for moto-x (done by previous owner)

Chassis: renthal bars, odi lock on grips, stock pegs suck... saving up for different set.

Protection: Carbon fiber skid plate, acerbis front disc guard, cycra aluminum hand guards, aluminum radiator guards

Tires/Wheels: Stock rims, hubs, bearings, MT 36 front and rear tires

Driveline: Parts unlimited x-ring chain and sprockets

Electrical: Garmin 60cs gps, Trailtech vapor, led taillight/stop light

Cosmetic: Guts seat cover, yz 3.2gal baja tank, yz front and rear plastics

Miscellaneous: street legal

Comments: Goes good, gets the crap beaten out of it and comes back for more

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Model/Year: 2006 WR450

Engine: GYTR AIS blockoff, UNI air filter, snorkel removed, holes cut in airbox, gray wire removed, Barnum side panel

Carb: JD Kit blue needle on 3rd clip, 48 pilot, 170 main, JD accelerator pump o-ring (thick), Zip-Ty fuel screw

Exhaust: Dr. D slip-on


Suspension: Stock

Chassis: CR Hi-bend bars

Protection: Utah Sport Skidplate, Works Connection Frame guards, Acerbis Multiconcept handguards

Tires/Wheels: Black anodized Excel wheels, tires vary, heavy duty tubes

Driveline: Ironman rear Sprocket 13/49 Ratio

Electrical: Acerbis Cyclops headlight

Cosmetic: A few tasteful decals

Miscellaneous: Moose rear fender bag, Moose front shroud bag for desert riding. I absolutely love this bike! Coming soon is an IMS tank, IMS footpegs, and possibly trying a YZ header and exhaust cam.

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WR 400 2001 model

Stocky motor twin air filter

GYTR tail pipe stock headder

Run Thumper 20w50

Suspension std

Bar raisers and scott gripps RC high bars

B&B bash plate B&B rear disk guard

Stock wheels Michos front and rear 402's

14 52 gearing as std

MJ 170 PJ45 Just doing BK mod now as it bogs "Bugger"

Bike is other wise awsome in the bush just needs a button

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Model/Year:2006 450

Engine: GYTR AIS kit, No-Toil, snorkel & cut outs

Carb: JD jetting, Zip-TY air screw

Exhaust: stock, PMB insert

Fluids: yamalube, 50% glycol with water-wetter

Suspension: stock

Chassis: stock clamps with fat bar adapters, henry/reed bars, Tusk SS wide pegs, guts tall

Protection: pro-bends

Tires/Wheels: Maxxis IT desert rear, Dunlop 739 front

Driveline: stock

Electrical: none

Cosmetic: looks like crap


Comments: love it

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