Make your Yamaha rule the trees By the staff of Dirt Wheels


It takes a special type of talent and drive to be a GNCC pro ATV champion and an even rarer sort of person to win multiple titles in a row. As you might imagine, winning those championships also takes a very special sort of YFZ450R. No matter what quad you ride, you can learn from a quad champion like Walker Fowler. His race quad is tuned and tricked 100 percent to suit his kind of racing. The mods are not just about performance; to win, you must first finish. So, you will see a number of modifications that are designed to ensure that his quad will be running hard at the end of a two-hour sprint through the woods that makes up a GNCC racecourse.


Walker Fowler is the current GNCC XC1 Pro ATV champion, and he looks set to repeat his victory in 2016.


Even if you have no interest in racing your quad in the woods or anywhere else, certainly longevity should be important to you. After all, don’t we all want to finish the ride? Walker is a long-time proponent of the Yamaha YZF450R, so he knows what its strengths and weaknesses are. There is no reason to gusset the stock frame or swingarm. Like many Lonestar-sponsored (LSR) Yamaha riders, Fowler utilizes their DC-Pro billet spindles. They allow his YFZ-R to turn on a dime. Fox Float shocks (Gen 3) give it an aggressive but plush feel to the quad, along with the LSR DC-Pro A-arm makes for an impressive ride. In woods racing your body will take some hard hits. Using the Precision Pro stabilizer along with the Fasst Company Flexx handlebar allows Walker to feel as fresh as when he started the two-hour-plus race by damping the abuse. Walker relies on Cycra Probend handguards and BRP billet mounts. The combination protects both his hands and the quad’s vital hand controls. A Works Connection clutch perch/lever has a bearing that offers smooth clutch action.


Many of the critical mods are up front: Fox Float Gen 3 shocks, LSR A-arms, stem, spindles and hubs, and the Flex bar with Cycra guards. The radiator is usually covered to keep it from packing with mud.



It’s crucial to get a great start in the GNCC series. The riders have a dead-engine start, and if you don’t have the correct equipment, starts can be very slow. Walker’s YFZ-R has an aftermarket 24-volt starting system that starts this monster very quickly. This was one of our favorite features of the #1 machine. Most of the power of a sport ATV will depend on the head porting and valve selection. Moto-Xperts has been with Walker for a long time, and with all of that testing they have a great powerplant for XC racing. Even with all of that power, it’s very rideable and predictable. To complement the engine mods, a full FMF 4.1 RCT exhaust system is installed. It gives the Yamaha improved power and sound to boot. With big power you’ll need to feed this steed with more air and fuel. A Vortex ECU is installed, and it is a great option since you can change the settings in a jiffy. In the air department, Walker likes the improved flow that Fuel Customs and a GYTR filter provides. Since Walker’s pro races are around 2.5 hours long with quick pit stops in between, he needs a quick way to get in and out of the pit. IMS provides him with a dry-break system with an oversized tank, much like one you see in NASCAR. The quicker the pit, the less worry he’ll have that someone will pass him. His mechanic Mark Notman has some of the quickest pit stops there are!


XC racers probably use their clutch more than most other racing disciplines. This is where the importance of a good clutch comes in. A GYTR full clutch kit helps put the power to the ground for hours on end.  Pro Taper sprockets are used front and rear with gearing that will be changed for each round due to different course conditions. With how muddy GNCC races can be, a solid chain is a must, and Walker’s chosen setup is a D.I.D X-ring chain.

The rear end of the machine needs performance that equals the front of the quad. A Fox Podium rear shock complements the front Floats as they work in unison to conquer the rough terrain. Lonestar’s Axcalibar is a great adjustable rear axle that is stronger than stock and looks great as well. LSR (Lonestar Racing) also provides Walker with billet-aluminum hubs front and rear for strength.


Fowler runs a proprietary engine-management package, Moto-Xpert head mods and an FMF exhaust. Wheel covers prevent the wheels from filling with mud.


Tire and wheel selection is a big deal. Walker has trusted Maxxis tires for years, running the Razr2 in the front and the Razr XC in the rear. This tire combo provides great traction in most terrain. The tires are mounted on Hiper Tech3 carbon fiber beadlock wheels front and rear, and they have Tire Balls installed for flat prevention. This option also allows Walker to run lower tire pressure for better traction. Stopping this beast is not easy. DP brake pads were installed to tame it down for upcoming corners or obstacles.

Custom sprocket and rotor guards keep the quad’s rear end safe, while a GYTR poly-frame skid plate allows him to glide over rocks and logs. To keep Walker’s feet planted and safe, LSR provides him with the DC-Pro nerf bar/heel guard combo. A Moto Seat Wave seat cover keeps him glued to his seat even in muddy situations. If you’ve ever raced in the woods, you know that trees can “jump out at you!” Walker is prepared with LSR’s front bumper and rear grab bar.


Rider: Walker Fowler

Bike builder: Mark Notman

Contributors: N-Fab, Maxxis, AmPro, Yamaha Motor Corp, Lonestar Racing Products, MXP, MSR, Fox Shox, FMF, Hiper, Web cams, DP Brakes, Cycra, IMS, GYTR, Yamalube, Outerwears, Motoseat, Works Connection, Fasst Co., AntiGravity Batteries, Vortex Ignitions, VP Race Fuel, ODI Grips, Hill International Trucks, D&V Trucking, Precision Stabilizers, Graphic Worx, Fuel Customs, CV4, Atlas, Wiseco, Tire Balls, Scott Goggles, Bell Helmets, D.I.D. chain, TM Designs, Evans Coolant, Waynesburg Yamaha


Quad: 2016 Yamaha YFZ450R

Moto-Xperts: (765) 230-0514,

MXP custom porting & head mods: Price varies


Ignition/timing—Vortex ECU: $799

Fuel Customs: (909) 594-6082,

Airbox/intake: $325


Filter: $58

4-stroke oil—Yamalube Semi Synthetic 10w50: $10.50 per qt.

Full GYTR clutch setup: $800

Skid plates—GYTR frame skid

FMF Racing: (310) 631-4363,

Exhaust—FMF Factory 4.1 RCT full system: $700

VP Racing Fuels:

Fuel—VP price varies


D.I.D. Chain:

Gold ATV X-ring: Price varies


Sprockets: $92


Lonestar Racing: (480) 834-2990,

LSR spindles—DC-Pro $650

LSR steering stem: $362

LSR hubs: $535

LSR rear axle—Axcalibar: $399

LSR footpegs—DC-Pro w/ nerf bars and heel guards $275+

LSR front bumper: $55

Fox Shox: (831)274-6500,

Fox front shocks—Gen 3: $1600

Fox rear shock—Gen 3: $1000

Precision Racing Products: (209) 365-1850,

Precision Pro steering stabilizer: $560


Maxxis Razr 2 21×7-10 front: $179

Maxxis Razr 20×11-9 rear: $141

Hiper Technology: (877) 464-4737,

Hiper Tech 3 beadlock wheels: $990

DP Brakes:

DP brake pads: Price varies

Fasst Company: (877) 306-1801,

Handlebars/bend—Flexx handlebars 15-degree Quadracer low: $359.99

Cycra Racing:

Handguards—Cycra Pro bends: $83

Works Connection: (530)642-9488,

Clutch lever—Works Connection: $156

Motoseat: (951) 677-8325,

Seat cover—Moto seat: $70

IMS Products: (800) 237-9906, 

Tank—IMS tank with dry break complete: $500.51

ATVATV RacingChampionCycra RacingFasst CompanyFMFFuel InjectedGNCCGYTRHiper TechnologyIMSLonestar RacingMaxxisProTaperWorks ConnectionYamahaYFZ450