2006 Honda CRF250R

2006 Honda CRF250R: Twin Pipes and a Serious Engine Update

The 2006 Honda CRF250R was a significant update rather than a simple carry-over model. Honda kept the basic Unicam four-stroke architecture and aluminium twin-tube chassis concept introduced with the original CRF250R, but made substantial changes to the engine, intake, exhaust and chassis layout. Visually, the defining feature was impossible to miss: the 2006 bike introduced Honda's distinctive twin-muffler exhaust system.

Honda promoted the twin exhaust primarily as a mass-centralisation measure. Instead of hanging one larger silencer farther out and rearward, the two smaller mufflers allowed more exhaust mass to be positioned closer to the centreline of the motorcycle. The concept was intended to reduce the effect of that mass during roll, pitch and yaw, particularly through whoops, direction changes and jump transitions. Whether every rider could feel the claimed difference was debatable, but the twin-pipe layout instantly made the 2006 CRF250R one of the most recognisable motocross bikes of its era.

The engine changes were more important than the exhaust styling. Honda increased the compression ratio from the earlier specification to 12.9:1 and fitted a revised piston with a thinner ring to reduce friction. The cylinder head, valve-seat arrangement, camshaft and ignition mapping were also revised. Fuel delivery moved from the earlier 37 mm carburettor to a larger 40 mm Keihin FCR flat-slide unit with throttle-position sensing. Owners maintaining the original system can use the MXOwners carburettor reference when looking at replacement and service options.

Honda was clearly chasing a stronger and broader powerband. The early CRF250R had established itself as a capable race bike, but competition from Yamaha and the rapidly developing 250 four-stroke class meant Honda needed more torque and stronger acceleration. The 2006 engine revisions were aimed particularly at improving low and midrange response while retaining the high-rpm character required in 250-class motocross.

The chassis also received detail changes intended to complement the engine work. The radiators were positioned lower, the subframe and airbox arrangement were revised, and Honda continued to refine weight distribution and rider movement. The Showa suspension remained serious competition equipment, with a 47 mm inverted twin-chamber fork and Pro-Link rear shock offering extensive damping adjustment. Correct fork-oil quantity has a noticeable effect on bottoming resistance and end-stroke firmness, making the MXOwners fork oil reference useful during suspension servicing.

For modern owners, the 2006 CRF250R is also a machine that rewards careful maintenance. The high-compression, high-revving Unicam engine uses separate engine and transmission lubrication systems, and valve-clearance inspection is especially important. The standard NGK R0409B-8 spark plug is a specialised racing plug, while transmission oil capacity is only around 0.60 litres after a normal drain. Keeping the foam air filter properly cleaned and oiled is essential to protecting the valves, piston and cylinder from dirt ingestion.

The 2006 model has become an interesting point in CRF history because it combines the mechanical simplicity of a carburetted motocross four-stroke with some of Honda's most distinctive experimentation. The dual exhaust would become closely associated with several generations of Honda motocross bikes, while the larger FCR carburettor and revised engine formed the basis for further refinement in following years. Owners rebuilding one today can use the MXOwners parts finder to help identify year-specific replacement components.

Rather than being an all-new generation, the 2006 CRF250R was a heavily revised evolution of Honda's original 250 four-stroke motocrosser. Its combination of higher compression, larger carburettor, revised engine internals, altered mass distribution and signature twin mufflers makes it one of the more historically distinctive CRF250R model years from the carburettor era.