2004 Honda CRF250R

2004 Honda CRF250R – Honda’s First 250 Four-Stroke Motocrosser

The 2004 Honda CRF250R was a major new model and the first CRF250R in Honda’s motocross range. It arrived as four-strokes were rapidly taking over the 250 class and gave Honda a purpose-built machine to compete directly with the new generation of lightweight 250 four-stroke motocross bikes.

At the centre of the new CRF250R was a compact 249 cc liquid-cooled engine using Honda’s Unicam cylinder-head design. With a 78.0 mm bore and 52.2 mm stroke, four titanium valves and a high compression ratio, the engine was designed to rev hard while keeping the cylinder head narrow and relatively light. This architecture became one of the defining features of Honda’s CRF motocross range.

Fuel was supplied by a 37 mm Keihin FCR flat-slide carburettor with an accelerator pump. The FCR offered strong throttle response but required correct jetting, fuel-screw adjustment and accelerator-pump setup to perform at its best. Owners maintaining an original induction system can compare replacement carburettor options if the stock carburettor is worn, damaged or incomplete.

Honda built the new machine around an aluminium twin-spar frame derived from its larger CRF and CR motocross bikes. The aim was to combine low weight with strong rigidity and predictable handling. Showa suspension was used at both ends, with a 47 mm inverted fork and Pro-Link rear shock offering extensive adjustment for competition use.

The front suspension provided approximately 315 mm of travel, while the rear offered around 320 mm. Correct fluid condition and damping setup are important on these early CRF250Rs because worn suspension can dramatically change how the bike behaves under braking and through rough terrain. Owners servicing the front end can use the MXOwners fork oil reference when checking suitable oil information.

The 2004 CRF250R also introduced a very different maintenance routine compared with Honda’s two-stroke motocross bikes. The engine used separate engine and transmission oil systems, and regular valve-clearance inspection, air-filter servicing and frequent oil changes became essential parts of ownership. The highly tuned Unicam engine was designed for racing rather than long road-style service intervals.

Standard motocross wheels were 21 inches at the front and 19 inches at the rear, fitted with 80/100-21 and 100/90-19 tyres. Owners checking modern replacements can use the MXOwners tyre size guide, while the MXOwners Parts Finder can help identify suitable components for maintenance and restoration.

Historically, the 2004 CRF250R was the beginning of one of Honda’s most important modern motocross model lines. It did not immediately replace Honda’s two-stroke machines, but it marked the direction the sport was heading. The combination of a high-revving Unicam engine, aluminium chassis and advanced Showa suspension established the basic formula that Honda would continue refining for many years.