The Ultimate Four-Stroke Weapon - Suzuki RM-Z450
by Staff Writer

Introducing the all-new RM-Z450, it is another step toward establishing Suzuki's dominance in four-stroke motocross racing.

The RM-Z450 offers supremely balanced performance - strong, controllable power delivery complemented by extraordinarily lightweight handling. In fact, the RM-Z450 is extremely lightweight - and it has incredible performance to match. That combination means you can launch out of corners with breathtaking acceleration and attack the nastiest sections of the track with total confidence. The Suzuki RM-Z450 is loaded with advanced technology to make it remarkably easy to ride. It Includes the Suzuki Advanced Sump System, the Suzuki Active Vent System, lightweight and durable titanium valves, hollow billet camshafts and much more.

The four-speed RM-Z’s engine produces explosive power that is not as smooth as the others; in fact, it is a little rough around the edges. Not there is anything wrong with that—it gets you around the track, and in a hurry!

The bike features a compact 450cc, 4-stroke, liquid-cooled, DOHC, 4-valve engine. It is lightweight in design with emphasis on broad power delivery. The narrow cylinder head design featuring shim-under-bucket valve train with titanium valves reduces reciprocating mass and gives a more stable high-rpm performance. The lightweight hollow-type camshafts with carburized surface treatment for durability and high lubrication qualities contribute to the precise valve operation at all engine rpm. The durable forged-aluminum piston with tin plating and oil retaining grooves reduce friction and wear. The electro-plated aluminum cylinder bore increases durability and heat transfer. The Keihin FCR40 carburetor comes with a hot start system and the throttle-position sensor is linked to the digital CDI ignition. The bike has a lightweight exhaust system with titanium head pipe with large-capacity stainless-steel secondary pipe and aluminum muffler. The automatic decompression system, similar to RM-Z250, is designed for easy kick starting and durable operation. The Suzuki Advanced Sump System is a semi-dry-sump lubrication system. It features a separate crankshaft and transmission oil chambers which, permits low crankshaft placement for reduced engine height and low center-of-gravity. The Suzuki Active Vent System, a one-way reed valve system between crankshaft and transmission, reduces crank chamber pressure and enhances piston ring seal performance and overall engine power. Four-speed transmission for weight reduction and compact engine size allows the clutch to be placed closer to the engine centerline to concentrate engine mass and reduces crankcase area required for transmission. The counterbalancer shaft gear, driven off the magneto rotor, reduces engine vibration without adding to engine size or weight.

The ergonomics are comfortable, though a little cramped for taller riders. Frame and suspension complement each other, resulting in an efficient, predictable ride, whether on a rough or smooth track. The bike’s mass is spread evenly and low, keeping it manageable in any situation. If you like to tuck around the inside of corners, this is the bike for you.

The bike has an attractive aluminum twin-spar frame designed for optimum strength, rigidity and weight. The aluminum swingarm with tapered beam design similar to RM250 features a cast-aluminum cross beam to improve straight-line performance. The RM250-type rear suspension linkage—suspension load placed on the swingarm instead of the frame—reduces weight, and allows smoother movement of the rear shock and linkage for improved rear wheel traction. The new lightweight chain guide design similar to RM125/250, cutaway design, reduces weight. The bike has a Showa-brand cartridge-style front fork with 47mm inner tube, plus 22-way compression damping, 20-way rebound damping and 12.2 inches of wheel travel, wherein the internal structure is similar to the RM250. The Showa-brand rear shock absorber with large 50mm piston and 18mm inner rod increases oil flow and provides stable damping performance. The large 250mm front disc brake reduces weight and high durability. It also includes a Kevlar brake hose for low expansion rate and improved brake lever feel. The rotor is mounted at four points instead of six with new-type shouldered bolts for a secure fit and minimal weight. The bike has a compact 240mm rear disc brake with lightweight caliper body similar to the RM-Z250. The rotor is mounted at four points instead of six with new-type shouldered bolts for a secure fit and minimal weight. The new-style wheels, spokes and spoke nipples provide the best balance of weight, rigidity and overall wheel strength. The new-style front and rear wheel hubs reduce weight and added strength. They also provide a more rigid assembly when combined with larger axle, new spoke design and wide wheel bearing pitch. The specially-designed Bridgestone tires with large contact patch improve traction and acceleration - 90/100-21 front, 120/90-19 rear—wider than competing models without weight increase. The Renthal tapered aluminum handlebars with Renthal-labeled handlebar pad, which is lighter than standard bars, are rubber-mounted to reduce vibration. The titanium footpegs provide high grip and minimal weight. The slim fuel tank shape blend with the seat and radiator shrouds for easy rider movement and weight transition. The new-design rear fender and frame covers, with fresh air vents, increase air flow to the carburetor airbox. The shouldered aluminum spacers provide quick and secure mounting of body work.

The all-new RM-Z450 is the bike you get when you combine Suzuki's championship-winning motocross program with the legendary GSX-R four-stroke road-racing program.