2015 Yamaha YZ450F Review
The 2015 Yamaha YZ450F marks the second year of the newest generation of Yamaha’s premiere motocross machine. With a thorough overhaul in 2014, Yamaha’s engineers aimed to make small, but effective, improvements for 2015. The changes made to the 2015 YZ450F include revalved forks, a remapped ECU, new motor mounts, a 48-tooth rear sprocket, black Excel rims, a roller type gear-stop lever, a new throttle return spring, and Dzus fasteners on the airbox.
The 450cc DOHC engine has a four-valve head and rearward slanted top end, and easily fires to life with a firm, yet thorough, kick. The engine is incredibly fast, yet the powerband is linear. The YZ450F’s bottom end, mid-range, and top end are all strong making it one of the easiest powerplants to adjust to quickly and ride with confidence.
Because of these attributes of the powerband, cornering is made that much easier whether you are hugging the inside or railing the outside line. I found it best to utilize first or second gear on tight inside lines, and either second or third gear for the outside. Nearly any obstacle is possible regardless of the conditions as a twist of the wrist gets the YZ450F moving in a hurry.
The strong, linear powerband that the Yamaha engine makes is incredible and the new 48-tooth sprocket, down a tooth from last year, helps contribute to the linear feeling as well as the remapped ECU.
The stock pipe has a nice bark to it, and helps the engine breath easily. For those looking to tinker with the Yamaha’s power curve, the accessory GYTR Power Tuner does the trick. You can’t use it to get more overall power than stock, but you can adjust the power curve to your liking.
Shifting through the five-speed transmission on the YZ is made easier via the implementation of a roller type gear-stop lever. The gears are spaced out very well, which makes for less overall shifting needed. Aside from that, shifting through the cogs is simple and straightforward. I did not miss a shift during my time spinning laps on the Yamaha YZ450F.
The Kayaba Speed-Sensitive System (SSS) forks are the best in the class. The forks work incredibly well in the corners and are unbelievably plush on big jump landings. They are also incredibly forgiving if you manage to come up short on a jump as well. The forks feel incredibly plush and get progressively stiffer throughout the stroke. Conveniently, there is no need to check fork air pressures before a moto. In an era where air forks are becoming the norm, Yamaha’s decision to stay with standard coil springs forks is proving to be a smart one.
The Kayaba rear shock works wonderfully in unison with the SSS forks. The shock is incredibly plush on the big landings, yet tractable in the tightest of corners. Preload and clicker adjustments are easily accessed via the left side of the YZ450F thanks to the reversed cylinder head.
The 2015 Yamaha YZ450F handles very well, which is complemented by the fantastic suspension. Cornering ability has been improved upon from last year, thanks to the reshaped steel motor mounts allowing for slightly more flex in the front of the frame. With this change, the front end feels more planted when cornering. The bike does feel a bit wide at the front due to the radiator shrouds, which double as the airbox. However, I quickly became accustomed to this after my first few laps.
In the ergonomics department, the 250mm front brake could be improved upon to help stop a bike with such a strong engine. Anyone who desires stronger front braking will want to invest in an oversized rotor, such as a Moto Stuff 280mm Blade Oversize Brake Kit. The stock YZ450F rear brake works like any good rear brake should, and did not fade during a moto.
Clutch pull is smooth, and refuses it to slip or need adjustment. The clutch lever has a gradual curve and lacks a defined place to pull in. Luckily, levers are an easy replacement if the rider finds himself searching for a definitive, consistent place to pull the clutch in.
The front brake lever has a much more defined bend and feels much easier to modulate with the index finger. The bars have an agreeable bend that most riders will feel comfortable with. The grips are a little harder of a compound for my liking, but that too is easily and inexpensively changed.
The 2015 Yamaha YZ450F’s throttle pull is noticeably easier, thanks to the new throttle return spring. The Dunlop Geomax MX52 tires hook up well at all of the tracks I tested at, which included multiple types of terrain ranging from soft and loamy to a more intermediate, harder-packed track. Both the front and rear rubber held up well and maintained a sharp edge after many rides.
Maintaining the YZ450F is slightly different than other bikes due to the airbox being located up near the front of the bike. Access the air filter involves unscrewing three Dzus fasteners, which allow the top of the airbox to be removed. The new Dzus fasteners make swapping an air filter a quick and easy task that does not require any tools.
Changing the oil involves unscrewing the 12mm drain bolt located on the bottom of the engine. Changing the oil filter requires the removal of two 8mm bolts located on the right side of the engine. Refilling the engine with oil is done so by removing the oil filler cap on the left side of the engine on the crankcase cover.
Beginner and novice riders will feel comfortable racing the Yamaha YZ450F due to its linear powerband and balanced suspension. Intermediate and Pro riders will love the YZ450F due to its incredibly powerful engine and plush front forks and rear shock.
The 2015 Yamaha YZ450Fs incremental improvements proved to be worthwhile after the complete overhaul it received in 2014. Each of the changes prove to be effective on the racetrack in order to make the rider feel more comfortable and confident in order to push the bike to its limits. With an engine that makes tons of power and class- leading suspension that can be appreciated by all levels of riders, the 2015 Yamaha YZ450F is a great choice for anyone looking for a fast, well-suspended bike that is designed to go the distance.
Photography by Don Williams at Pala Raceway
- Helmet: Vemar VRX9
- Goggles: Oakley Airbrake MX
- Neck Brace: Leatt-Brace GPX 5.5
- Jersey, pants and gloves: Moose Racing Racewear Sahara
- Boots: Sidi Crossfire 2 SR
Andrew Oldar is sponsored by Moose Racing.
2015 Yamaha YZ450F Specifications
- Engine…449.7cc liquid-cooled DOHC 4-stroke w/ 4 titanium valves
- Bore x stroke…97.0 x 60.8mm
- Compression ratio…12.5:1
- Fueling…Yamaha Fuel Injection, Keihin 44mm TCI
- Transmission…Constant-mesh 5-speed; multiplate wet clutch
Front…KYB Speed-Sensitive System, inverted fork, fully adjustable, with 12.2″ travel
- Rear…KYB fully adjustable single shock w/ 12.4″ travel
- Brakes Front…Hydraulic single disc brake, 250mm
- Brakes Rear…Hydraulic single disc brake, 245mm
- Front tire… Dunlop Geomax MX52, 80/100-21
- Rear tire… Dunlop Geomax MX52, 120/80-19
- Seat height…38.4 inches
- Wheelbase…58.3 inches
- Ground clearance…13.2 inches
- Fuel capacity…2.0 gallons
- Wet weight…245 pounds
- Colors…Team Yamaha Blue/White; White/Red
- 2015 Yamaha YZ450F MSRP…$8490
2015 Yamaha YZ450F Review Photo Gallery