This is Suzuki’s 2008 RM-Z450: the first production motocross machine to feature electronic fuel injection.
The Suzuki RM-Z450 started life as a new Suzuki model: A four-stroke motocross bike, totally different from any two-stroke RM model, not just engine wise but even the frame and almost every detail of the bike is specially designed for the competition motocrosser.
Big brother to the RM-Z250, with aluminum frame instead of steal, the bike was presented in Japan in June 2004 and available in the shops in Japan July 29th.
It had a 449cc, four stroke, single-cylinder, liquid cooled, DOHC, 4-valve per cylinder engine and it was equipped with a 4-speed transmission.
The KEIHIN FCR40 fuel system had the duty to provide the engine with the exact amount of fuel needed.
The bike kept its characteristics and it became very popular in the following 2 years of fabrication and competition but for 2008, Suzuki engineers planed to improve the low-to-mid range power with a battery-less fuel injection system. For a better use of the new fuel injection system the combustion chamber was increased and it does the job properly.
But all that power needed a better continuity and a few more mph so the bike received a hole new five speed gearbox for 2008, improving the performance of the bike.
The handling will also be improved thanks to the new, lighter frame front suspension and redesigned, thinner swing arm. This bike will feel lighter, faster and a bit anxious to ride the bumps on the track.
When it entered the most hotly contested class in the dirt bike market, the RM-Z was looking to upset the Honda CRF450, which had a stranglehold on the class, if not the entire MX market. Honda had beaten Yamaha on this class and Suzuki had the same plans with Honda. Prototypes started to be developed, improved and tested and Suzuki was on the right track but about the same time the 2005 Honda CRF450R hit the magazine test circuit, and word spread like wildfire about how improved this machine was. Still, the Suzuki engineers were seen even more frequently, causing some to speculate that they were changing the bike even more.
It’s finally landed-Fuel Injection has arrived on production motocross machines, with the introduction of the all-new 2008 RM-Z450 from Suzuki.
Unveiled at Suzuki’s European press conference in Rome earlier this week, the all-new RM-Z450 has rewritten the history books in the holy contested MX 1 class, offering fuel injection from the manufacturer acknowledged as THE expert.
Grippes seat has been improved this year by adding projected cross-shaped patterns on the top surface to provide additional grip.
The front number plate design helps guide fresh air to the radiators for better cooling performance.
Front fender incorporates a sloped-down shape to efficiently guide wind to the front number plate air ducts for improved cooling performance. The rear fender incorporates air intakes on both sides for heighten intake efficiency while tying in a fresh new look.
New 2-tone molded-plastic radiator shrouds give the RM-Z450 a slim feel and stylish look for 2008 while also complimenting an all-new graphics design and color way. Also, the redesigned outer lover plates offer better cooling performance by improving airflow to the radiators.
The newly designed pegs include increased clearance between the mounting bracket and footrest to prevent mud from caking up.
The bike’s chain is gold-colored and gives a full factory look.
The 2008 model is provided with new features like the hot start lever relocated to the right hand side of the handlebar for easy operation while holding the clutch and race inspired wave-rotors which provide better cooling performance and increases mud deflections in muddy conditions.
The engine is equipped with Electronic Fuel Injection offering better roll on power and improved low-to-mid range power, KEIHIN throttle body specifically designed for motocross and an internal fuel pump with a battery-less system.
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 a better handling.
Intake port angle and cam timing are revised and result in reduced intake resistance and heightened intake efficiency. Exhaust port and cam timing are designed to regulate exhaust pulses for maximum engine performance.
Flywheel inertia increased to produce a smoother engine and improve overall acceleration fell.
The combustion chamber was also redesigned for a better power output and improved low-to-mid range response. Narrower intake and exhaust valve angle guides along with increased squish areas improve air/fuel mixing and faster flame-propagation speed when mixture ignites.
For a reduced engine height which means a low center of gravity the Semi-dry-sump lubrication system features separate oil chambers for the transmission and the crankshaft uses the transmission as the oil sump, allowing low crankshaft placement.
But the most innovating and interesting technical feature for the RM-Z450 is the battery-less fuel injection system featuring a single-phase all-charging system with which the magneto supplies all of the necessary power.
The 18-pin magneto senses feedback on crankshaft position, rotation speed and stroke which is fed back to the ECU to calculate optimum injection and ignition timings.
The bike also has a new Chassis:
The all-new frame is lighter and has improved rigidity balance for incredibly agile handling and unmatched performance over bumps.
Showa cartridge-style front fork is fully adjustable for rebound, compression and preload settings and designed for reduced weight and improved shock absorption.
The rear swing arm was also redesigned and it is now thinner, lighter and ready for the bumps.
Dimensions and weight
Overall length: 2185mm (86 in)
Overall width: 830mm (32.7 in)
Overall height: 1260mm (49.6 in)
Wheelbase: 1480mm (58.3 in)
Seat height: 955mm (37.6 in)
Dry Mass: 101kg (222.7 lbs)
Fuel capacity: 6.2litres (1.4 gallons)
Engine and transmission
Engine capacity: 449cc
Engine type: 4-stroke, liquid cooled, DOHC
Compression ratio: 12.8:1
Lubrication: Suzuki Advanced Sump System
Clutch: Wet multi-plate type
Ignition: Digital AC-CDI
Fuel System: KEIHIN FI 43mm
Transmission: 5 speed, constant mesh
Front suspension: Showa 47mm telescopic, pneumatic/coil spring, oil damped
Rear suspension: Swing arm, link type, SHOWA piggyback-reservoir shock
Front brakes: Single hydraulic disc
Rear brakes: Single hydraulic disc
Front tyre size: 90/100-21
Rear tyre size: 120/80-19
We were not able to ride the bike yet but I promise we will soon. As you can suppose, having all the information and characteristics of the previous models, the RM-Z450 is a very strong, reliable and powerful bike. The 2008 version was designed for better handling and light weight: it has a new, lighter frame, a thinner swing arm on the back and brand new suspension in the front so it probably handles like a dream.
The bike’s price has not been announced yet.
Suzuki knows how increasingly competitive motocross is, but the challenge to keep winning races and championships is what motivates engineers to strive for perfection.
Championship winning experience off-road and on, give Suzuki a unique advantage, bringing GSX-R technology from the chicanes and hairpins to the berms and whoops.