2005 Suzuki RM-Z450

The much-anticipated Suzuki RM-Z450 was finally shown to dealers at the company’s annual dealer show in Las Vegas last night. None other than factory Suzuki motocross star Travis Pastrana (pictured), paraded the bike across the stage in front of the huge gathering of cheering dealers.

The RM line of motorcycles were introduced in grand form, as five bikes wheelied and jumped across the stage in a stunt-filled presentation. The cool thing was that the riders were factory Suzuki racing stars, but when the helmets came off it was four-time AMA Superbike Champion Mat Mladin, Ben Spies and Aaron Yates joining Pastrana for the introduction - not the company’s motocross regulars.

The star of the show had to be the new four-stroke RM-Z450 motocross bike. The bike follows in the footsteps of its little sibling the RM-Z250, which was introduced last season. The motor is a 449cc liquid-cooled, DOHC design with four titanium valves. The valve train features a shim under bucket design for improved high rpm performance and ease of maintenance, and also features a narrow 26-degree included valve angle. The camshafts are a hollow design to reduce reciprocating mass at high rpms. The forged aluminum pistons slide up and down in electro-plated aluminum cylinders. The engine is a semi-dry sump design similar to the Honda CRF450, with separate oil chambers for the crankcase and transmission oil. It features an automatic decompression system similar to the system on the RM-Z250 for easy starting. Carburetion is handled by a Keihin FCR40 unit that features a throttle position sensor linked to the CDI ignition, and features a hot-start system for easier starting after a stall or tip-over. The transmission is a four-speed design similar to the unit in the Yamaha YZ450F, in an effort to reduce the size of the motor and to reduce weight. The motor also features a shaft gear driven counter balancer to keep things smooth.

The chassis features a brand new aluminum twin-spar frame with a forged steering head, main spars, and front engine mounts, combined with extruded rear shock mounts, and pressed aluminum down tubes. The rear suspension features a RM250 type rear linkage mated to a fully adjustable Showa rear shock with 12.2-inches of suspension travel. Up front is a 47mm Showa fully adjustable fork with 12.1-inches of travel. Braking is handled by a 250mm disc and twin-piston caliper in the front, which is pumped by a new Kevlar brake line. Out back is a 240mm disc and single-piston caliper. The bike features Renthal tapered aluminum fat bars with a standard Renthal pad, which mount in rubber mounted clamps. The trick looking footpegs are made of titanium for reduced weight. The claimed dry weight is 220 pounds, which should make the RM-Z450 competitive with the other Japanese and Austrian competition. The bike will retail for $6499