of the glass wool packing. The 2013 RM-Z450 meets both the 115 dB two-meter-max and 94 dB SAE sound tests. In MXA’s sound test, it pumped out 115. 4 dB wide open (well within the 1 dB correction factor) and 93 dB at 4500 rpm. Airbox. The air boot is reshaped and enlarged to aid airflow, while the back panel of the airbox is made of a carbon matrix material to reduce intake noise compared to the previous plastic airbox. Fork. The 2013 RM-Z450 uses Showa Separate Function Forks (SFF) with separate spring and damping tasks. The right leg contains the spring, while the left leg incorporates the cartridge assembly to manage damping. The single-spring design results in reduced friction and a weight savings. The fork-tube diameter is increased from 47mm to 48mm, and the spring preload is adjustable. These forks have been used on the Kawasaki KX250F for the last two years. Dust covers. The rear axle and top steering-head bearings have new seals to resist mud and dirt intrusion. Q: WHAT WOULD MXA HAVE LIKED SUZUKI TO FIX FOR 2013? A: We are happy that Suzuki addressed its long- standing gearbox issues and tried to beef up the midrange power, but there were other issues that also needed attention. Maybe next year Suzuki will put some money into these four problem areas: (1) Clutch. Suzuki’s clutch is marginal at best. Even when brand new, it is spongy and feels like it is always on the verge of slipping. We had to resort to stiffer clutch springs to keep the pack together. ( 2) Overheating. The stock 1.1 kpf radiator cap isn’t sufficient to prevent boiling. We immediately switched to a 1.6 kpf cap (and suggest that every RM-Z450 owner do the same). Strangely, Suzuki’s engineers did modify the RM-Z250 cooling system with a new radiator hose layout, different fin pitch and a new bypass design. ( 3) Rear-brake adjustment. Suzuki’s rear-pedal adjustment has a very narrow window. If you miss it, the rear brake will burn up. Caveat: There must be freeplay in the master cylinder’s slotted clevis. ( 4) Weight. The RM-Z450 is the heaviest of the “Big Five” 450s—even heavier than the battery-equipped electric-start KTM 450SXF. It tipped our scales at 242 pounds. Q: HOW DOES THE 2013 SUZUKI RM-Z450 RUN ON THE DYNO? A: The 2013 Suzuki RM-Z450 produced 54. 10 horsepower on the dyno with 34. 99 foot-pounds of torque. If you are into playing the numbers game, the 2012 RM-Z450 pumped out 54.08 horsepower and 35. 11 foot-pounds of torque. Based purely on numbers, there is not much difference between the two machines, but peak dyno numbers don’t tell the whole story. At 54. 10 horsepower, the Suzuki is no match for the 55.18-horsepower KTM 450SXF or the 55.05-horsepower Kawasaki KX450F.
2013 Suzuki RM-Z450: For 2013 Suzuki tried to fix
some—but not all—of their flaws while bringing the
power down lower in the curve.