Images courtesy of Suzuki

A few weeks ago we saw the first glance of the 2015 Suzuki RM-Z450 with the standard press release images and text, but at Glen Helen the Japanese brand invited the media to a full briefing on the latest bike. This marks the tenth installment of the popular machine, which has earned many honors (TWMX Bike of the Year), championships, and innovations (first production bike with EFI). From the outside the big bore bike looks no different than years past, but there are in fact many improvements to the engine, suspension, and chassis.


The RM-Z is widely praised as one of the most agile bikes on the market and this is a trait that Suzuki aimed to keep while reducing weight from the chassis. The weight of the frame alone has been reduced by four percent, but tweaks to the inner ribs and downtube allow the bike to keep the same rigidity and balance. Minor changes have been made throughout the rest of the chassis as well, including redesigned engine mount brackets, swingarm, foot pegs, engine protectors, and rear brake guards.


After years of development in the professional circle, Showa's SSF Air Fork sees its first production implementation in the RM-Z 450. The revolutionary suspension component is the most striking feature of the 2015 machine, a part once only reserved for the sport's fastest riders. By eliminating the traditional coil spring for a series of chambers, rods, and pistons, the SFF Air Fork is an astounding two pounds lighter than the SFF fork used in 2014.

Changing the spring rate to a rider's preference is incredibly easy, as it can be adjusted with a simple air pump. Stability comes through design that separates the spring and damper functions, keeping the air spring away from the heat of the damper.


Earlier this year we spotted a flashing light on the handlebars of James Stewart's handlebars, but our requests for information were shot down by Suzuki brass. We assumed that it was a start function, and the first look of Suzuki's Holeshot Assist Control is just like what it on JS7's bike. Developed through racing experience, the two settings will let the rider optimize the power of the bike for the conditions. The "A" setting yields a smoother response from the engine, perfect for slippery conditions or a novice rider. The "B" settings unleashes the power with an aggressive delivery, best when there is plenty of traction behind the gate.

One common complaint with the Suzuki RM-Z 450 pertains to issues with starting, and Suzuki made a number of changes to the mass of moving parts to improve the problem. The layout of the starter idle gear has been changed, and the kick gear ratio, decompressor, and exhaust camshaft have all been revised. On the outside of the engine is a kick lever pulled straight from James Stewart's bike, which is been extended 30mm than the 2014 model for easier action and an increased radius.

Keeping a thumper cool is a massive concern and Suzuki's latest plumbing will optimize the flow of coolant by sixteen percent. Radiators on each side will see equalized flow, thanks to a revised hose connection and pump cover. The flow of coolant now goes directly between the pump and right radiator.

Some have described shifting under power as "notchy", and Suzuki has taken on the problem by increasing the precision of their gear matching for the transmission for smoother runs through the gears. The final change comes to the exhaust on the US models, which have an inner pipe installed at the base of the silencer to meet AMA sound regulations.

Suzuki's intentions with the 2015 RM-Z 450 were to bring technology straight from James Stewart's race bike to the production line. Parts like Excel wheels, Renthal bars, wave brake rotors, and optional rich and lean couplers make the bike race-ready from the showroom floor, and the company's response to the industry's concerns show they want to remain the one to beat.

For more details, visit the bike’s microsite at