2015 Suzuki RM-Z450 Preview

When Suzuki released the 2005 RM-Z450 – its first four-stroke motocross machine – the bike went on a winning streak, taking four AMA Motocross and two AMA Supercross titles.

Piloting the then-new machine to the championship wins were some of the most iconic names in the sport – Ricky Carmichael, Chad Reed and Ryan Dungey.

Since its introduction, though, the RM-Z450 only received one major update. The update arrived in 2008 when the RM-Z450 became the first motocrosser to get fuel injection.

But with competition growing stronger from rival manufacturers such as KTM and Honda, Suzuki has revamped the 2015  Suzuki RM-Z450 for a higher level of performance. The overhaul is highlighted by Suzuki Holeshot Assist Control technology and Showa SFF Air Fork.

Suzuki says its engineers also redesigned a number of other components on the 2015 RM-Z450. The MX motorcycle receives a longer kickstart lever, revised kick-gear ratios, updated de-compression system, a redesigned exhaust camshaft, which combined improve engine starting.

Suzuki didn’t stop there. Cooling was improved by 16 percent due to a revised system. The enhanced cooling is attributed to fluids traveling more effectively between the right and left radiator halves, plus an updated water-pump cover and revised hose connection directing coolant directly into the water-pump.

The 2015 RM-Z 450 has also slimmed down a bit due to the new Air fork that features no coil springs, and a redesigned frame. The new machine has a curb weight of 247 lb. Also, the redesigned muffler complies with AMA sound control.

The Suzuki Holeshot Assist Control is one of the major improvements on the RM-Z450. Through electronically altering the ignition timing, the SHAC provides better launch traction. The SHAC – which has two modes and off – is programmed with specific commands that return ignition timing to normal operation and let riders power into and through the first turn.

Riders engage Suzuki Holeshot Assist Control from a button on the left-side handlebar: Mode A is for slippery launch conditions, and alters ignition timing; Mode B is for good grip conditions and advances ignition timing.

Mode A returns to normal ignition timing after 1.2 seconds, or when the rider reaches third gear. Mode B returns to normal ignition timing after 4.5 seconds, or when the rider reaches fourth gear.

The other big news is the Showa SFF Air Fork, which was tested and proven by factory racers, including Yoshimura Suzuki’s James Stewart.

Speaking of the new fork, Suzuki says it “delivers more progressive suspension feel and offers infinite adjustability in a package that’s nearly 2.5 pounds lighter than the conventional spring fork. Adjustments to the SFF-Air fork can be made easily with use of a hand-held pump.”

Suzuki says the 2014 RM-Z450 continues to feature key components such as Suzuki Fuel Injection with two additional plug-in fuel couplers feeding a 449cc liquid-cooled four-stroke engine with dual overhead cams, as well as the comfort, confidence and control of Renthal FatBars, Excel aluminum rims, and waved disc rotors.

As for the price of the new RM-Z450, it has yet to be determined.

2015 Suzuki RM-Z450 Specs:

  • Overall Length: 2190 mm (86.2 in)
  • Overall width: 830 mm (32.7 in)
  • Overall height: 1270 mm (50.0 in)
  • Wheelbase: 1495 mm (58.9 in)
  • Ground clearance: 325 mm (12.8 in)
  • Seat height: 955 mm (37.6 in)
  • Curb mass: 112 kg ( 247lbs)
  • Engine type: 4-stroke, liquid cooled, DOHC
  • Bore x stroke: 96.0 mm x 62.1 mm (3.8 in x 2.4 in)
  • Engine displacement: 449 cm3
  • Compression ratio: 12.5 : 1
  • Fuel system: Fuel injection
  • Starter system: Primary kick
  • Lubrication system: Semi-dry sump
  • Transmission: 5-speed constant mesh
  • Primary reduction ratio: 2.625 (63 / 24)
  • Final reduction ratio: 3.846 (50 / 13)
  • Suspension Front: Inverted telescopic, air spring, oil damped; Rear: Link type, coil spring, oil damped
  • Rake / trail: 28° 40’
  • Brakes: Front – Disc; Rear – Disc
  • Tires: Front – 80/100-21 51M, tube type; Rear- 110/90-19 62M, tube type
  • Ignition system Electronic Ignition: (CDI)
  • Fuel tank capacity: 6.2 L (1.6/1.4 US/Imp gal)
  • Oil capacity (Overhaul): 1.2 L (1.3/1.1 US/Imp gal)