Engine Design Concept
For race-winning performance, a motocrosser’s engine needs to be durable, efficient and powerful. To win championships, that engine needs the powerful engineering heritage that comes from Suzuki. The RM-Z250 features a fuel-injected engine powered by Suzuki's advanced technology. Suzuki’s fuel-injection expertise has delivered national and world championships in Superbike racing as well as in Motocross and Supercross. High-performance heritage like this serves as the platform for the technological improvements of the RM-Z250 delivering increased acceleration, faster throttle response, and broader mid-range power and torque. That means motorcycles that are more competitive and more practical performers to win those bar-to-bar battles.
Increasing the exhaust pipe’s length by 40mm for the RM-Z250 has resulted in a better tuned engine to deliver stronger low-end and mid-range power output. A new silencer has a redesigned construction with inner pipes that meet FIM-enforced sound control regulations without jeopardizing engine power output.
Based on racing data and on-track experience, Suzuki redesigned the piston of RM-Z250. With a new shape – designed through Finite Element Method (FEM) analysis used in factory racing – new piston is 3% lighter than in the previous model while retaining rigidity. It has slightly thinner skirt walls, a shorter piston pin and narrower piston pin boss to help cut weight but not sacrifice performance and durability. A reinforcing rib on the intake underside adds rigidity; the exhaust underside is left alone for best lubrication and cooling efficiency.
Transmission & Shift Cam
RM-Z racers will enjoy smoother and more precise shifting on the 2013 RM-Z250 as it has been upgraded with an all-new 5-speed transmission and the shape of the shift cam has been changed to deliver shifting precision plus a smoother shift feel.
Suzuki updated the electronics that help control the battery-less fuel-injection system. The new ECM on now has a higher-performance processor for more powerful engine management. This component upgrade increases response all the way from the rider’s throttle input to the fuel delivery through the multiple hole fuel injector. And since the ECMs are now waterproof, they resist damage from water and mud, and that helps keep racers at the front of the pack. The electrical systems also has a new magneto with increased power-generating performance for easier starting. And with revised settings in the ignition coil, the RM-Z250 delivers strong roll-on power and increased throttle response.
Both intake and exhaust cam profile are changed on RM-Z250. The nose angle and lift curve of intake camshaft is increased and exhaust cam timing is revised to achieve higher balance between high performance and ease of power control.
The RM-Z250’s cooling efficiency is increased thanks to a redesigned radiator fin and revised water hose routing, making the bike’s high-performance power output more stable, even in the most demanding conditions. The RM-Z250 also features a new by-pass hose routing to simplify occasional radiator maintenance.
Chassis Design Concept
Racers know that, in and out of a corner, precision cornering and race-track stability has always been a prime feature of Suzuki’s motocross bikes. But that doesn’t mean engineers left “good enough” alone. For 2013, the team focused on making the RM-Z250 even more maneuverable, while retaining the bike’s top-notch performance tracking and race-speed stability. With enhanced engine performance as well as refined handling control, the RM-Z250 will continue to be the choice of champions, and of those soon-to-become champions.
To ensure the frame’s rigidity is well balanced, engineers reviewed and refined the shape and construction of the frame and the seat rail. The result is an ideal balance of nimble handling for technical sections and straight-line stability for high-speed sections.
The RM-Z250 now uses the new Showa Separate Function front Fork (SFF). The SFF works by separating the damper in left leg from the spring housed in the right leg. Dividing the fork’s functions allows for lighter overall construction with reduced friction, resulting in improved damping performance and ride control. The forks’ inner tubes are now 48mm in diameter; the larger size gives higher stability. Spring pre-load is adjustable, by gold-anodized adjuster, allowing a wider range of adjustment settings overall.
To maintain the RM-Z250’s renowned handling performance, the rear suspension features to option for setting changes and adjustments to best match the increased engine performance and front fork changes. Overall, the design allows enhanced suspension performance for a wider variety of riders.
To see a video about the new RM-Z250, click here.
To see a video about the new RM-Z250 from our friends at Suzuki America, click here.