The Honda CRF450X is all-new this year, and we had the opportunity to test it this past October in the Mojave Desert of Southern California. Prior to the bike's overhaul in 2019, the CRF450X remained largely the same from when it was first introduced in 2005. The CRF450X has been the most successful bike in Baja with 11 Baja 1000 victories and another nine wins in the Baja 500.

Project bike builder Jay Clark purchased a 2007 Honda CRF450X off of Craigslist with the goal of making it as fast and as strong as an R model by using several parts from a variety of different companies. We rode it at an off-road riding area in Southern California after some rain and were impressed with how a bike more than a decade old performed with some aftermarket components and proper tuning.

The main modifications done to the CRF450X were cutting the airbox open to allow more airflow and cutting the pink wire on the ECU. According to Clark, the pink wire retards the ignition about three degrees and cutting it is an easy way to make the bike faster. Additionally, the backfire screen was removed, a smog elimination kit was installed, and the odometer was taken off with the R model front axle installed in its place. Listed at the bottom of the article are the jetting specifications along with the full list of parts Clark used on the build.

2007 Honda CRF450X
Project bike builder Jay Clark purchased a 2007 Honda CRF450X off of Craigslist this past summer.Mark Kariya

The first thing we noticed when riding Clark’s creation was how quickly it revved. Because of this, we found ourselves shifting quickly on fast straightaways. Due to the bike’s plentiful amount of torque, we were able to leave it in third gear in most corners as it had more than enough grunt to comfortably pull it. This enabled us to avoid quickly pulling through second gear and having to shift to third immediately coming out of corners.

2007 Honda CRF450X Project Bike
Clark’s goal was to make it as fast and as strong as an R model. He sought to achieve that by adding several aftermarket components from a variety of companies.Mark Kariya

The Factory Connection-massaged suspension components worked well. The fork maintained a plush feel, even on slap-down landings, while the shock stayed planted in slower and high-speed situations alike. The CRF450X was built to dominate Baja, so it understandably favors straight line stability. We were also impressed with how well it cornered too. Overall, Clark did a great job of bringing this more-than-a-decade-old bike back to life. The amount of power the bike has is comparable to most current year 450cc off-road motorcycles, but with a more sudden delivery that’s not as linear or controllable as a fuel-injected bike. The suspension performance allowed for a comfortable and predictable ride, and the plethora of aftermarket goodies made it look great as well.

cutting open the airbox
One of the main modifications done to the CRF450X was cutting open the airbox to allow more airflow.Mark Kariya

Jetting Specifications

  • 48 pilot
  • 42 leak
  • 160 main
  • Stock needle with 1mm shim underneath in the middle clip
  • 2 turns out on fuel screw
backfire screen was removed
The backfire screen was removed, a smog elimination kit was installed, and the odometer was taken off with the R model front axle installed in its place.Mark Kariya
old-school four-stroke engine
The bike revved quickly, yet retained the old-school four-stroke character of the prior-generation carbureted CRF450X.Mark Kariya
2007 Honda CRF450X Project Bike
Clark’s project bike turned decently, but it favored straight-line stability, a testament to the CRF450X being designed for the high speeds of Baja.Mark Kariya
Vertex high-compression piston kit
One of the main aftermarket components used inside the engine was a Vertex high-compression piston kit, which included the rings, pin, and clips.Vertex
Hot Cams Stage 2 camshaft
A Hot Cams Stage 2 camshaft further increased power.Hot Cams
All Balls Racing carb
Clark used an All Balls Racing carb rebuild kit as well.All Balls

Parts List

Vertex Pistons
High-compression piston kit (ring, pin, and clips): $199.95

Hot Cams
Stage 2 camshaft: $269.95

All Balls Racing
Carburetor rebuild kit: $44.16
Throttle cable: $18.88
Clutch cable: $16.22
Linkage bearing kit: $83.78

Cometic Gasket
Top end gasket kit: $89.38

FMF Racing
Megabomb stainless steel header pipe: $274.99
Factory 4.1 RCT aluminum slip-on muffler: $399.99

Front sprocket: $19.95
Stealth gold rear sprocket: $97.95
Enduro O-ring gold chain: $84.62

IMS Products
Core footpegs: $159
3.2-gallon fuel tank: $274.95

DeCal Works
Semi-custom graphics kit: $269.90
Preprinted number plate backgrounds: $39.95

UFO Plastic
Full plastic kit: $231.94
Headlight: $120

Works Connection
Factory II stand: $119.95
Front brake cap: $27.50
Rear brake cap: $24.95
Rotating bar-clamp front brake: $27.50
Steering stem nut: $29.95
Radiator braces: $79.95
Elite axle blocks: $59.95

Dunlop Tires
AT81 front, 90/100-21: $123.95
AT81 rear, 120/90-18: $118.95

Uni Filter
Air filter: $32.95

TM Designworks
Rear chain guide: $79.95
Rear disc: $104.95
Rear caliper guard: $43.95
Skid plate: $117.95

Hinson Clutch Components
Full clutch setup including cover: $1,144.99

Seat cover: $64.95

Motion Pro
Titan throttle tube: $24.99
Grip glue: $8.99

604 Fatbar: $91.95
Tacky grips: $20.95

Factory Connection
Suspension rebuild and service: $700

Enduro Engineering
EVO2 black debris deflectors with 7/8" clamp set: $67.95
EVO2 black plastic outer mount roost deflectors: $24.95

Complete wheelset: $559.99
Oversize rotor with adaptor bracket: $149.99
Rear brake rotor: $99.99
Front brake line: $69.99
Lithium battery: $115.99

Trail Tech
Radiator fan: $189.95
Kickstand: $149.95