Suzuki has announced the 2018 RM-Z450. Though there’s sadly no news of any RM-X450 enduro bike, the motocross machine gets an all-new chassis, a Showa ‘Balance free’ Shock, updated engine plus an improved holeshot assist, traction management and fresh new styling for 2018.
Updates to the chassis look pretty extensive with a 700g lighter frame. A new swingarm sees a further weight saving of 100g to contribute the improved handling all round.
The subframe gets a new stronger hexagonal structure, slimmer design it improves the overall look of the bike plus makes it easier access to the air filter.
The 2018 RM-Z450 becomes the first production motocross machine to adopt Showa’s premium Balance Free shock absorber, which uses an external damping circuit to avoid variations in the balance of pressure and therefore improves oil flow, controls absorption and increases traction.
The Showa forks arrive, or rather return, to a coil spring set-up, replacing the air forks which promised so much just a few short years ago. Fork diameter is increased from 58.5mm to 59.3mm to improve responsiveness and feel for the rider.
The wheelbase is now shorter too, 1480mm from the 1495mm. With the headstock moved 10mm backwards and the handlebars moved 7mm forward these are fundamental changes to set-up. Bars remain Renthal, but are straighter and flatter to allow riders to easily shift their weight over the front of the bike.
A new resin fuel tank (was aluminium) reduces weight by 275g and increases capacity from 6.2 litres to 6.3 litres. Lighter front and rear wheels save 70g, 34g are saved with a new top yoke, 30g with a new chain guide, and 246g with a new seat.
The 270mm front brake disc is 20mm bigger and new rear brake master cylinder should improve braking performance.
The 2018 RM-Z450 engine promises higher peak power, more low-midrange torque and improved throttle response.
New and smoother porting in the cylinder head has increased tumble flow by 25% helping efficient combustion and higher peak power without sacrificing low-to-mid range power. A 30% larger air filter aperture is a step forward and helps increase power output through the revs. A new intake cam profile helps too raising valve lift and improving intake efficiency. A new piston was also needed to cope with the higher peak power output.
Throttle response is improved thanks to a variety of changes, including a new fuel pump which increases fuel pressure by 17% and promotes more effective mixing of air and fuel. There’s also a new throttle body and fuel injector, which now injects fuel upwards and directly onto the butterfly valve.
The latest version of Suzuki’s holeshot assist system adjusts ignition timing and offers two modes for riders to choose from, depending on the conditions. A-mode on hard surfaces or in slippery conditions retards ignition timing for a smoother launch. B-mode is for use in grippier conditions and advances ignition timing during launch. The system is operated by pressing and holding a switch on the bars and returns to normal six seconds after the launch, when the rider shifts into fifth gear, or when the throttle is closed.
The 2018 RM-Z450 also gets an evolved version of Suzuki’s traction management system. The ECM boasts 1.6x faster data processing and 2.5x the memory capacity. It monitors throttle position, engine speed, and gear position and controls ignition timing, fuel injection rate and engine output depending on riding conditions (it differs from road-going traction control in that it does not monitor rear wheel spin).
The RM-Z450’s new sharper design bodywork imitates the factory race bikes.
The new RM-Z450 is forecast to arrive in dealerships in the autumn.
Jon PearsonEnduro21 tester of things