Bike: 2015 Kawasaki KX250F & KX450F

Kawasaki’s 2015-model KX250F and KX450F machines have broken cover in the US. Here’s what you need to know about ’em:

2015 Kawasaki KX450F

The Kayaba PSF Air Fork used on the 2014-model KX450F has been replaced by a Showa Separate Function Fork (SFF) with a Triple Air Chamber (TAC), that separates the damping forces into the left fork tube, while the pneumatic spring is housed on the right tube for less friction, better movement and a lighter fork. The Showa SFF-Air Fork also appears on Suzuki’s 2015 RM-Z250 and RM-Z450 models, as well as Honda’s 2015 CRF250R. The rear Showa shock has revised valving for firmer damping.

The Bridged Box piston has been revised, and the ECU system has been upgraded for 2015, with new programming to enhance traction control. Push-button launch control returns on the 2015 Kawasaki KX450F.

A lighter rear subframe is shared with the 2015 Kawasaki KX250F. It’s aimed to reduce the weight and improve mass centralisation for a more nimble feel. A 270mm, oversized, petal-shaped front brake rotor will replace last year’s 250mm front rotor. It is paired with a 240mm rear brake rotor. These changes also appear on the 2015 Kawasaki KX250F.

A self-locking rear axle nut replaces the castle nut previously used. The axles, which are new for 2015, are lightened by 31 grams on the front and 32 grams on the rear.

The 2015 KX450F’s look is highlighted by factory-style graphics, green engine, oil cap and generator plugs, as well as green alumite suspension adjusters and black alumite wheels.

2015 Kawasaki KX250F

The 249cc engine receives a new, reinforced Bridged Box piston borrowed directly from the factory race bikes. The exhaust system gets a shorter header pipe equipped with a resonance chamber to enhance low-end power. The KX250F uses the KX450F’s high-volume muffler to assists with mass centralisation and make better top-end power.

The ECU system has a new magneto rotor with greater inertia to match the increased acceleration performance. Kawasaki’s Dual-Fuel (DFI) injection system utilizes two injectors that deliver a second squirt of fuel under acceleration to maximize the engine’s power. Push-button launch control returns on the 2015 Kawasaki KX250F.

The Showa Separate Function Fork (SFF) has new valving. These are not Air forks, but instead have a coil spring in the right fork leg and oil damping in the left leg. The rear Showa shock has firmer settings to match the front fork upgrades The shock features high-speed and low-speed compression damping and a self-lubricating alumite coating on the inner surface of the shock cylinder wall, to avoid abrasion, reduce friction and smooth the suspension action.

The 2015 KX250F has a new four-position upper triple clamp with two sets of handlebar mount slots. These offer the rider the choice of four bar positions, including 25mm forward, 15mm forward, standard or 10mm back. Plus, the KX250F borrows the two-position, adjustable footpeg brackets from the KX450F. The footpegs can be lowered 5mm on the frame.

Kawasaki’s 2015 KX250F’s look replicates the 2015 KX450F.

—

Stay tuned for an Australian release date and pricing structure. We’ll have a detailed full-length ride impression on both machines in the next issue of Transmoto Dirt Bike Magazine (September-October, #46). For now, check out Racer X Online‘s top-line reviews on the significantly upgraded KX250F and KX450F models, put together by regular Transmoto contributors, David Pingree and Matty Francis.