2013 Suzuki RM-Z450
Kawasaki has been using the Showa Separate Function Fork (SFF) on the KX250F since 2011. Suzuki is taking a play out of the Kawi book by slapping the SFF on the RM-Z450. Suzuki’s new front suspension is a 48mm unit (previously 47mm) which houses the spring in the right fork leg and the valving in the left fork leg. The big benefit of this design is the ability to alter the spring preload on the front which changes the ride height and affects handling. The fork is also lighter and the single spring and cartridge reduce friction. The 2013 Honda CRF450R and 2013 Kawasaki KX450F both get new a new fork as well, but they employ the Kayaba Pneumatic Spring Fork, making the Suzuki the only SFF design in the 450 class.
The SFF suspension holds the spring and
valving in different fork legs. RM-Z250 engine
changes are highlighted in yellow.
The Showa rear shock has updated settings to match the new fork. Engineers also worked on the aluminum chassis to balance the rigidity through frame and seat rail adjustments.
Suzuki also massaged the 450 powerplant. The single-cylinder engine gets a new piston that is 13% lighter for a fast-revving delivery and increased bottom-to-mid power. The connecting rod is also tweaked and the piston pin gets a DLC surface treatment for better durability. Cam timing and lift is changed on the intake to smooth power delivery. The RM-Z450 still makes use of fuel injection and comes with three different couplers that change the fuel settings (stock, richer, leaner). It uses a kickstarter to fire up and runs at 12.5:1 compression ratio.
The transmission gets a reshaped shift cam, stopper spring an drive shaft. As a result, Suzuki claims the five-speed is more precise and solid in gear changes.
2013 Suzuki RM-Z250
The 250 also gets the SFF, transmission upgrades, chassis tweaks and comes with the mapping couplers. The engine gets similar treatment as well, the piston is 3% lighter, with additional changes to the exhaust cams and the clutch cam release is modified for a lighter pull and improved feel. The 250 also gets an improved cooling system courtesy of a new radiator fin and revised water hose routing.