Kawasaki KFX450R – A true Team Greenie builds a masterpiece By the staff of Dirt Wheels Photos by Papperazzi Imaging and Films/ and Karel Kramer

Kawasaki kfx450R
Massachusetts’ Al Tranghese is making the world greener one Kawasaki KFX450R at a time. He’s had over 20 of them, but this is the one to rule them all. He rides as well as he builds!

Albert Tranghese barely missed the three-wheeler era, but embraced quads in general and Kawasaki quads specifically as a teen. His first machine was a 1988 Kawasaki Tecate 4 two-stroke. As hard as that was, Tranghese remained loyal to Team Green, aside from 2005 to 2007. He felt the KFX400 was no longer competitive, so he raced Honda TRX450Rs. 

Tranghese spent a lot of time, effort and money to get the seat down so he can turn the KFX450R like this. His mods let him move around easily for the best body positioning. Photo by Papperazzi Imaging and Films

As you can imagine, it was good news for Tranghese when Kawasaki entered the 450 class in 2008 with the first KFX450R. The model remained in production until 2014. Unlike some other brands, the KFX450R was narrow for trails, and it was the only Japanese 450 sport quad with reverse. It was designed to be agile in the woods, and that suited Tranghese’s riding style. He found the KFX was nimble and felt lighter in the air than other brands.

Kawasaki KFX450R
PRP Racing from New York created the one-off swingarm and the custom subframe. The front of the swingarm is dimensionally KFX, and the rear is Honda TRX 450R! Everything at the rear of the swingarm is Honda-spec’d.


With the help of Baldwin Motorsports, the KFX450R motor was competitive right from the start. While the KFX engine has a family relationship to the KX450F motocross engine, it is quite different. It was fuel-injected, while the KX (and KLX) were still carbureted in 2008. According to Tranghese, the KFX had a much beefier transmission.

Unfortunately, the KFX450R’s arrival coincided with the collapse of the housing market and resulting in a recession. The KFX450R never sold in huge numbers, though it did stay in the Kawasaki lineup until 2014. Kawasaki may have given up on the KFX, but Tranghese never has. Since 2008 he has owned at least 20 KFX quads. Four of those have been his personal track and race machines. The rest were restorations that are part of his one-man crusade to keep the meanest green quad alive. He has even started to develop parts that make it easier to keep a KFX working well and feeling fresh, and has a website supporting those products.


This latest build is the most modified and farthest from stock of the four track quads he has built. For a time there was a factory Kawasaki race team campaigning the KFX450R. Many exclusive products were developed for the machine that made it a significant threat for MX racing. Tranghese has made it a mission to chase down those Team Kawasaki special parts that remain.

He insists that Kawasaki has very good parts support for the KFX for those who plan to keep them stock. The aftermarket runs on numbers, though. If it takes too long to sell through a specialized part, when they are gone, there is no motivation for the builder to produce more. Many of the modifications to this stunning KFX are the last part of its kind or close to it. Some of the companies still have parts for the KFX, but they are not “Team Kawasaki” spec, or are as far from stock as this machine is.

Kawasaki kfx450R
Tranghese carefully cares for and maintains the Baldwin head and modified throttle body on this machine. He always runs this head on his favorite MX quad. The engine makes monster power without tuner or injector mods.


Many of the most custom modifications are to reinforce the bike or to arrange the ergonomics to Tranghese’s liking. In his opinion the KFX seat is high and the handlebar is low. PRP Racing out of New York made the subframe and the swingarm. Now the seat is 3 inches lower at the grab bar. Up front the handlebar is farther back and 30mm higher at the grips.

Tranghese also has his reasons for the PRP-fabbed swingarm. He has broken stock ones, so the PRP version is stronger. From the front pivot to the linkage, this swingarm is dimensionally Kawasaki. From the linkage to the rear axle, the swingarm is Honda. Everything on the back axle is Honda. Not many guys race the Kawasaki. If Tranghese has a problem at the track, it is probable that he could find some Honda parts if needed. Honda’s rear caliper is a performance upgrade, but the rest is for convenience. There is vastly more aftermarket support for the Honda rear, so it is much easier to get parts and in more variety. The rear uses stock Honda TRX hubs as well.

The DWT wheels have very little offset to keep the ball joints in the center of the rim. That choice maintains a legal width, eases bump-steer, and minimizes the load on the wheel bearings and ball joints.


Kawasaki Monster Energy Team race quads used a special Roll Design front end with A-arms that are +1 inches and keep the track 50 inches wide. Those A-arms mate with Team spindles made by Kawasaki for these special Roll Design Team A-arms. Neither the spindles nor the A-arms were ever made for the public. Baldwin made a few front hubs like these, but they are no longer available. All A-arm hardware is custom-made titanium race-team issue.

Rolling stock is thanks to DWT Champion in a Box wheels with bead-lock rears running ITP motocross tires. Fortunately, Kawasaki and Honda sport quads share a bolt pattern, so there is no problem with the Honda-rear, Kawasaki-front-hub arrangement.

It is fortunate that Tranghese has enough parts to build one more Team front end like this one. Now that this quad was completed, been photographed, has taken a cross-country riding and tuning trip to California and back, it is being retired.

Kawasaki KFX450R
Many of the most unique and custom modifications are to get the riding position where Tranghese wants it. The rear of the seat is 3 inches lower than stock! Roll Design handled the front end and all of the custom-tuned Elka Stage 5 shocks.


While this quad is being retired, it will park with another motor in the frame. Tranghese only has one KFX Baldwin Motorsports Pro head. It is fully modified with internal changes. Likely Baldwin will build a KFX head, but according to Tranghese, not one like this. Likewise, Baldwin modified a stock KFX throttle body, but it runs the stock injector. The modified throttle body requires almost no effort to actuate the thumb throttle. The Pro Circuit exhaust and the Hinson clutch cover are all Kawasaki Monster Energy Team pieces. The pipe is dimensionally the same, but lacks heat-shield mounts on the header.

Inside the head are Web cams. Under the head are a Wiseco piston. It uses a stock crank with a CP Carillo rod for strength. Everything in the bottom end and transmission is either cryo-treated or micro-polished. Under the Hinson clutch cover is a full Hinson billetproof conventional clutch setup.

Tranghese completed the engine with a brand-new factory wiring harness, stator, injector and regulator from Kawasaki. Baldwin made a tether switch with a harness that had factory connectors to mate with the stock harness. It killed the fuel pump, but it is no longer available, but this KFX has one.

Garrett Torres from Fuel Customs spent a lot of time optimizing the intake system. It uses a Fuel Customs intake boot mated to an ‘06-or-newer Honda TRX lower airbox. Another trick but unobtainable part is the oversize, true cross-flow GMX radiator from England. It has an integrated oil cooler as well. It is a sweet piece, but the company no longer makes ATV products.

Kawasaki KFX450R
Tranghese managed to locate Roll Design Kawasaki race-team A-arms and front spindles. They are controlled by Elka Stage 5 shocks with fully tuned and custom settings from Roll Design. The shocks are tuned to work with all adjusters all the way out.


Tranghese employs a Magura tapered Fatbar fitted with a Braking radial-style master cylinder like the Kawasaki Team used. This particular model is no longer available, but street bikes and Supermoto machines still use them, so something similar is available from Braking. The bar also has a Works Connection EZ clutch perch.

And remember, the throttle body has almost no thumb resistance. It is easy to use, but is not for beginners, especially with an engine making this much power.

Tranghese Designs parts show up as well with the logo-engraved throttle cover. The machine uses a Roll Design stem, but it is supported by bearings top and bottom, but that rebuildable lower stem bearing plate and upper stem bearing plate are Tranghese Designs products. The upper steering-stem clamp is larger in diameter with a self-lubricating plastic sleeve for the steering stem.

Tranghese also makes a billet, oversize seat-retainer button. It is hard-anodized to keep the seat attached under loads. His seat and subframe modifications do put a load on the seat-tank junction, so the button is especially helpful. He also sells seat pins and receptacles for the rear of the seat.

Tranghese is involved in the graphics, but not Al Tranghese. Instead, his son Al Jr. came up with a design that was brought to life by Aggressive Graphics. Both Trangheses say the company was great to work with. Aggressive does custom kits if you want them.

This quad is an experts-only machine. The suspension is for aggressive, hard-charging riders. The engine has a crazy snap to it, so it rips out of turns, throwing massive roost like this. It would be next to impossible to replicate this machine exactly.


A build like this takes 150 to 200 hours. A full rebuild like this takes time anyway, but making the various parts get along is unfailingly tedious. Once it was together, Tranghese wanted the suspension to work as well.

The Elka shocks came from Roll. When you get Elkas from Roll Design, they come with custom settings for the suspension. They are dialed in to your specification. Once Tranghese completed the machine, he hit the road for Roll Design in California. After the initial test ride, Roll matched the spring pressure and length. After another day of testing, there was a spring change, and the front shocks were extended 6mm. Finally, Roll came up with new shim stacks somewhat close to what Joel Hetrick runs.

This trick, oversized, true cross-flow radiator and oil cooler combination from GMZ Radiators in England is another of the rare parts of this quad that are no longer available. Tranghese has carefully hoarded and searched for rare KFX450R parts.

So, the shocks were custom for Tranghese to start, and then Roll made three changes, including spring changes, valve stacks and shock length. The final settings are dialed for the shocks to work with all adjusters fully open.

Tranghese Designs makes the grease-able upper and lower steering-stem supports. They use quality bearings and can be rebuilt. They keep the steering feeling tight and new.


Al Tranghese is an acknowledged expert on the Kawasaki KFX450R with information gleaned from many miles and hours riding, building and modifying this model. This machine is the pinnacle of his knowledge and experience. A machine with no time, labor or expense spared in the effort. Without reading the words, one look at this KFX would let you know that this is a KFX that any fan of green machines would worship. It is a beauty, but it’s far more than a show queen; rather, it’s a true weapon wrapped in artistry.

Kawasaki kfx450R


ACERBIS USA: (800) 659-1440,

MX Uniko vented handguards: $40.95

AGGRESSIVE GRAPHICS: (774) 314-1673,

Custom graphics: $183

BALDWIN MOTORSPORTS: (440) 224-2734,

Billet front hubs: N/A

Case saver: N/A

Tether harness: N/A

Custom cylinder head modifications: N/A

Bored throttle body: N/A

BCS POWERSPORTS: (413) 736-2201,

Custom-braided brake lines: $150

JT sprockets: $40

D.I.D chain: $84.99

’06+ TRX450R airbox: $57.75

TRX450R rear caliper: $135.42

TRX450R caliper stay: $57.38

BRAKING: (937) 704-1462,

Braking 16 front master cylinder: N/A

CP-CARRILLO: (949) 567-9000,

KFX450R connecting rod: N/A

DG Performance: (714) 577-7499,

National II front bumper: N/A

Rear grab bar: N/A

DWT RACING:, 800-race-rim/(760) 758-5560

Champion in a Box wheelset: $780

FUEL CUSTOMS: (909) 594-6082,

Kawasaki FCI intake: $239


KX500 radiator guards: $30.99

All factory OEM Kawasaki parts for the build

FOURWERX CARBON: (262) 501-9696,

SR carbon fiber hood: $190

Carbon fiber under shrouds: $195

Wave seat cover: $160

Titanium banjo bolts: $13.45 ea.

Rear carbon fiber plate: $65

Front carbon fiber plate: $50

Carbon fiber mud caps: $75 set


Custom oversized radiator: N/A

Custom oil cooler: N/A

HINSON RACING: (909) 946-2942,

Complete Billetproof conventional clutch kit: $1,094.99


Complete powder coat: $750

POLY-PLATING, INC: (413) 593-5477,

Complete hardware re-plating: $400

PRO CIRCUIT RACING: (951) 738-8050,

Team TI-4 full exhaust: N/A

PRP RACING: (315) 723-3475

Custom swingarm: $569

Custom lowered subframe: $449

Billet TRX450R axle carrier: $139

ROLL DESIGN: (760) 731-5920,

+1 steering stem: $299.95

Bar mount: $99.95

Elka Stage 5 shocks: $3,299.98

Team A-Arms for custom spindles: N/A

Titanium spacers and collars for A-arms: N/A

Team custom front spindles: N/A

RPM: (928) 771-9363,

TRX450R Dominator II axle: $509.99

TRX450R anti-fade brake hub: $230.42

TM DESIGNWORKS: (541) 772-4161,

KFX450R belly skid plate: $139

TORQ 1 RACING: (972) 429-0244,

Defy lock-on grips: $26.99

TRANGHESE DESIGNS: (413) 888-0444,

TD44 throttle cover: N/A

TD44 seat pin kit: N/A

Billet seat button: $39

Rebuildable stem bearing plate: $159

Stem clamp: $95

TD44 E-brake block-off plate: N/A

WISECO: (440) 951-6600,

Piston: $198

WORKS CONNECTION: (530) 642-9488,

1-2-3 EZ clutch perch: $156

Engine plug kit: $39.95

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