It reverberates like thunder and strikes like lightning. It's the RM-Z250, the four-stroke motocross weapon that's been taking the competition apart. The RM-Z250 has it all. An incredibly wide and strong powerband that lets you launch out of corners. Optimum engine braking. Exceptionally easy starting hot or cold. And a lightweight design for precision handling on the toughest tracks.

The RM-Z250 for 2005: it's taking the four-stroke world by storm!

New Engine

Straighter exhaust ports and extended center rib for intake ports to improve low to mid range engine response

Revised ignition timing and rev limiter setting for improved high rpm and over-rev performance

New clutch plate design and improved clutch spring material for better clutch action and feel

Improved throttle valve design and new stainless-steel throttle cable designed for low-friction throttle operation

Shot-peened 3rd and 4th transmission gears for increased durability

Stronger reinforced airbox design for increased durability and improved intake seal

New-design oil filter cover for simplified oil change maintenance - cover can be removed without removing the water pump cover or draining coolant

Larger radiators for increased cooling capacity and more stable engine operating temperature - radiators are 40mm longer with 17.8% larger core area

More durable muffler construction with improved packing

New Chassis

Steering head wall thickness increased from 2.6mm to 3.2mm for increased rigidity and improved handling performance

New low-friction fork oil seals for smoother action throughout the fork stroke

On-the-fly clutch lever adjuster added to clutch lever perch for rider convenience

New front brake lever shape for improved rider feel

Improved seat cover material for better rider grip and new seat foam material for improved comfort and durability

Wider handlebar mounting position for increased handlebar strength and bending resistance

Front fork clamp bolt position relocated to left/right sides for easier fork maintenance

Key Features

Compact 249cc, 4-stroke, liquid-cooled, DOHC, 4-valve engine - designed for easy-to-ride 4-stroke power

Advanced 4-valve cylinder head design with narrow 25-degree included valve angle and titanium valves

Cam profiles selected for a wide powerband with strong peak power

Composite-plated aluminum alloy cylinder for increased durability, optimum engine cooling and operating temperature

Forged, 2-ring piston designed for maximum oil retention and minimal wear, plus tin plating for added durability

Keihin FCR37 carburetor with throttle position sensor and accelerator pump

Automatic decompression system for easy kick starting

Semi-dry-sump lubrication system features separate oil chambers for the transmission and crankshaft using the transmission as the oil sump, allowing low crankshaft placement, reduced engine height and a low center of gravity

AC-CDI ignition system with two ignition maps automatically increases engine idle speed to reduce engine brake effect

Five-speed transmission featuring a ratchet-type shift mechanism designed for light shifting effort

Magnesium cylinder head, generator and outer clutch covers minimize overall engine weight

Lightweight exhaust system features a titanium and stainless steel construction, plus a repackable aluminum/stainless steel muffler

Lightweight perimeter-type frame with D-shaped upper spars that contribute to a slim design and improved position and rider mobility

Slim bodywork allows greater freedom of movement for the rider

Kayaba 48mm inverted, bladder-style front fork with special valve system to optimize internal pressure and damping performance throughout the stroke

Kayaba reservoir-type rear shock absorber with 16-way adjustable compression and rebound damping

Rear linkage system places the suspension load on the swingarm instead of the frame to reduce frame weight, and allows smoother movement of the rear shock and linkage for improved rear wheel traction

Aluminum swingarm with tapered hydro-formed beams, forged axle holder, plus cast and forged linkage components

Front disc brake system consists of a dual-piston caliper with 27mm pistons, master cylinder with large 11mm piston and thin Kevlar brake line for reduced weight and progressive brake feel

Lightweight rear brake system includes a dual piston caliper with 25.4mm pistons and durable forged brake pedal

Aluminum skid plate with plastic side guards and aluminum engine mounting plates