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Suzuki's 2008 RM-Z450: electronic fuel injection first for motocross

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July 3, 2007

Tested by Suzuki Factory riders

Tested by Suzuki Factory riders

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July 4, 2007 In a move that will see other manufacturers scrambling to keep pace, Suzuki has announced the first production motocross machine to feature electronic fuel injection. Developed in the automobile industry throughout the 1970’s and first introduced to road bikes in the early 1980’s in models such as Honda’s CX500TURBO, fuel injection offers better roll on power and improved low-to-mid range delivery. The new system featured in the 2008 RM-Z450 has been tested by Suzuki's factory riders and given the ultra-competitive nature of the motocross environment, where having a bike that's not capable of winning is just not an option, it’s almost certain that fuel injection will become standard throughout the motocross market in the not too distant future.

Improved low-to-mid range delivery is achieved via an internal battery-less fuel pump located inside the fuel tank and specially designed Keihin carburettor. Other revisions to the 2008 RM-Z450 engine include revised intake port and cam timing which reduces intake resistance to improves efficiency and boost engine performance. The flywheel inertia is also increased to produce a smoother revving engine and improve overall acceleration.

The combustion chamber has been redesigned for better power output and improved low-to-mid response and a narrower intake and exhaust valve angle, along with increased squish areas, improve air and fuel mixing.

The five-speed gearbox has a new link type shifting mechanism and the bike also features a new, lighter frame which has improved rigidity balance for better handling. In addition a redesigned rear swingarm with a thinner wall also adds to weight reduction.

The Showa rear shock is also new and features a redesigned damper case and modified internal structure for a better controlled feel and increased bottoming resistance.

2008 RM-Z450 Specifications:

  • *Overall length:* 2185mm (86.0 in.)
  • *Overall width:* 830mm (32.7 in.)
  • *Overall height:* 1260mm (50.0 in.)
  • *Wheelbase: *1480mm (58.3 in.)
  • *Ground clearance: *350mm (13.8 in.)
  • *Seat height: *955mm (37.6 in.)
  • *Dry weight: *101.5kg (224 lbs.)
  • *Engine type: *4-stroke, liquid-cooled, DOHC
  • *Bore:* 96.0 mm
  • *Stroke: *62.1 mm
  • *Displacement:* 449 cm3 (cc)
  • *Compression ratio:* 12.8:1
  • *Fuel system: *KEIHIN FI 43mm
  • *Lubrication system:* Suzuki Advanced Sump System
  • *Clutch: *Wet multi-plate type
  • *Transmission: *5-speed constant mesh
  • *Primary reduction ratio:* 2.625 (63/24)
  • *Gear ratio Low: *1.800 (27/15), 2nd: 1.471 (25/17), 3rd: 1.235 (21/17), 4th: 1.050 (21/20), 5th: 0.909 (20/22)
  • *Final reduction ratio:* 3.846 (50/13)
  • *Front suspension: *SHOWA 47mm telescopic forks, pneumatic/coil spring, oil damped
  • *Rear suspension:* Swingarm, link type, SHOWA piggyback-reservoir shock
  • *Caster: *25°30'
  • *Trail: *111 mm (4.4 in.)
  • *Front brake: *Disc
  • *Rear brake:* Disc
  • *Front tyre size: *90/ 100-21
  • *Rear tyre size: *120/ 80-19
  • *Fuel tank capacity: *6.2 L (1.6 US gal.)
  • *Body colour:* Champion Yellow No.2 (YU1)
  • About the Author
    Noel McKeegan After a misspent youth at law school, Noel began to dabble in tech research, writing and things with wheels that go fast. This bus dropped him at the door of a freshly sprouted Gizmag.com in 2002. He has been Gizmag's Editor-in-Chief since 2007.   All articles by Noel McKeegan
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