The Yamaha WR450F is an
off-road
Off-roading is the activity of driving or riding in a vehicle on unpaved surfaces such as sand, gravel, riverbeds, mud, snow, rocks, and other natural terrain. Types of off-roading range in intensity, from leisure drives with unmodified vehicl ...
motorcycle made by
Yamaha Motor Company
is a Japanese multinational manufacturer of motorcycles, marine products such as boats and outboard motors, and other motorized products. The company was established in 1955 upon separation from Yamaha Corporation (however, Yamaha Corporation ...
. It currently has a
liquid-cooled single-cylinder
A single-cylinder engine, sometimes called a thumper, is a piston engine with one cylinder. This engine is often used for motorcycles, motor scooters, go-karts, all-terrain vehicles, radio-controlled vehicles, portable tools and garden machinery ( ...
engine. First offered in 1998 at 400cc, it shared many components and design concepts with the
YZ400F
The Yamaha YZ450F is a four-stroke racing motocross bike built by Yamaha Motor Corporation. It was the successor to the previous YZ426F which was discontinued in 2003. It is credited by ''Cycle World'' and ''Dirt Rider'' magazines as the bike that ...
motocross model. It is basically the racing
YZ450F detuned slightly for more controllable power, with a headlight and lighting coil, softer suspension, a
kickstand
A kickstand is a device on a bicycle or motorcycle that allows the bike to be kept upright without leaning against another object or the aid of a person. A kickstand is usually a piece of metal that flips down from the frame and makes contact ...
, lower noise specifications, larger radiators and lower emissions. The WR in the name indicates a
wide-ratio gear box common to most
enduro
Enduro is a form of motorcycle sport run on extended cross-country, off-road courses. Enduro consists of many different obstacles and challenges. The main type of enduro event, and the format to which the World Enduro Championship is run, is a ...
or trail bikes and stands in contrast to the close-ratio gearbox essential to a
motocross
Motocross is a form of off-road motorcycle racing held on enclosed off-road circuits. The sport evolved from motorcycle trials competitions held in the United Kingdom.
History
Motocross first evolved in Britain from motorcycle trials competi ...
racer. Over the years the WR has benefited from the advances made in the YZ motocross version gaining displacement and advancements such as an aluminum frame and improved suspension. Over much of its life the weight of the WR450F has remained fairly constant ranging from 244 to 249 pounds
dry weight
Vehicle weight is a measurement of wheeled motor vehicles; either an actual measured weight of the vehicle under defined conditions or a gross weight rating for its weight carrying capacity.
Curb or kerb weight
Curb weight (U.S. English) or kerb ...
.
[
]
First generation: WR400F - 1998-2000
Yamaha introduced the WR 400F in 1998. The 400F is a four-stroke off-road motorcycle produced for three years, beginning in 1998 and ending in 2000 (only the YZ was upgraded to 426 cc in 2000). The WR400F is related to the YZ400F, a motocross model. Like the YZ400, it was considered to be a groundbreaking model in motorcycle history, ushering in the four-stroke era which ended the dominance of two-stroke engine
A two-stroke (or two-stroke cycle) engine is a type of internal combustion engine that completes a power cycle with two strokes (up and down movements) of the piston during one power cycle, this power cycle being completed in one revolution of t ...
s in motocross and offroad racing. While many modern performance four-stroke dirt bikes have been criticized for excessive rebuild costs and short motor lifespans, the Yamaha WR400F has an impressive record of reliability, often attributed to its steel valves and generous oil capacity.
Second generation: WR426F - 2001-2002
In 2001 the WR400F's engine was uprated and it became the WR426F increasing the displacement to for greater power and throttle response. A beefier YZ style clutch basket and plates than those on the WR400 improved clutch performance. Frame geometry was identical to the 2002 YZ250 and YZ426F with a 58.7 inch wheelbase and 14.7 inches of ground clearance. This was the last WR to make use of a manual compression release for starting.
Third generation: Yamaha WR450F - 2003-2006
For 2003, the engine displacement was increased to , the fuel tank was reduced to 2.6 gallons [ ] and the bike came with an electric starter as standard equipment. The 2005 WR weighed in at 244 pounds dry, the seat height was reduced to 38 inches and the fuel tank was decreased to 2.1 gallons.[ The 2006 WR weighed in at 249 pounds dry][ and produced 42 horsepower.
A limited production version of the WR450F was the WR450F 2-Trac, which featured 2-wheel drive. The gearbox output sprocket drove a short, fully enclosed chain to a pump, which in turn pushed the oil to the front hub via the pipe and back via the parallel pipe.] A maximum of 15% of the power was transmitted to the front wheel at any time. Yamaha planned on building 250 2-Tracs in 2004, but only a few were built, which were used for enduro
Enduro is a form of motorcycle sport run on extended cross-country, off-road courses. Enduro consists of many different obstacles and challenges. The main type of enduro event, and the format to which the World Enduro Championship is run, is a ...
racing. 2006 was the last year of the steel frames.
The 2003 and 2004 models were red sticker bikes in California.
Fourth generation: Yamaha WR450F - 2007-2011
For 2007, the WR gained an aluminum frame dropping the weight from 249 to 246 pounds.
In addition to the aluminum frame, the 2007 WR450F saw a revised dry-sump engine, with a new balancer, cylinder head, and camshafts with less lift and duration than previous generations and restyled plastics. 2009 saw new graphics, and 2010 was not sold in the US.
Fifth generation: Yamaha WR450F - 2012-2015
After 3 years of design, the all-new 2012 WR450F was released and featured a 2012 YZ250F frame, KYB SSS forks, fuel injection
Fuel injection is the introduction of fuel in an internal combustion engine, most commonly automotive engines, by the means of an injector. This article focuses on fuel injection in reciprocating piston and Wankel rotary engines.
All comp ...
, and an altered motor position. Per Yamaha's designers, the only modifications required to the YZ250F chassis were updated motor mounts.[ The engine was rotated back to move the ]center of gravity
In physics, the center of mass of a distribution of mass in space (sometimes referred to as the balance point) is the unique point where the weight function, weighted relative position (vector), position of the distributed mass sums to zero. Thi ...
and improve handling[
]
Sixth generation: Yamaha WR450F - 2016-2018
For 2016, the WR was given the reverse slant, 4-valve, fuel injected motor previously available in the YZ450F since 2010. Yamaha also introduced a new model, the YZ450FX, a more Enduro
Enduro is a form of motorcycle sport run on extended cross-country, off-road courses. Enduro consists of many different obstacles and challenges. The main type of enduro event, and the format to which the World Enduro Championship is run, is a ...
competition oriented version of the off-road 450 utilizing more design elements of the motocross model such as stiffer suspension while maintaining electric start and the 18" rear wheel.
For 2017, the WR450F largely remained the same, except for modifications to the air box cover as well as a change from silver to black rims.
For 2018, the WR450F remained similar to the 2016-2017 models, with a large distinction being that the bike was no longer available to register as green sticker in the state of California. 2018 also saw the removal of the kick starter.
https://www.yamahamotorsports.com/off-road/models/2016/wr450f
Seventh generation: Yamaha WR450F - 2019-2020
The 2019 WR450F saw a more powerful motor & updated frame.[ This generation no longer supports a kick starter. Other changes include a revised, more compact frame, new speed sensor, bigger fuel tank and one fastener airbox access.]
Seventh generation: Yamaha WR450F - 2021-Present
The 2021 WR450F saw new cylinder head, camshafts, piston and connecting rods. The 2021 also saw a revised chassis as well.[
]
See also
* Yamaha WR250F
The Yamaha WR250F is an off-road motorcycle made by Yamaha Motor Company. It has a liquid-cooled single nikasil coated cylinder engine. First offered in 2001, it shared many components and design concepts with the YZ250F motocross model. It is ...
* Yamaha YZ450F
The Yamaha YZ450F is a four-stroke racing motocross bike built by Yamaha Motor Corporation. It was the successor to the previous YZ426F which was discontinued in 2003. It is credited by '' Cycle World'' and ''Dirt Rider'' magazines as the bike th ...
* Yamaha YZ450FX
References
{{Yamaha motorcycles timeline
WR450F
Off-road motorcycles
Motorcycles introduced in 1998