2009 KTM 250SX

2009 KTM 250 SX: Suspension and Brake Refinement for a Proven Two-Stroke

The 2009 KTM 250 SX was primarily a refinement of the established 2008 machine rather than a new generation. The engine remained essentially unchanged, retaining the 249 cc two-stroke, 36 mm Keihin PWK carburettor, five-speed gearbox and hydraulic clutch. KTM instead concentrated much of its development effort on the chassis, suspension and braking package.

The WP 48 mm closed-cartridge fork received lighter inner and outer tubes, revised bottoming cones and changes designed to give the front end more controlled flex. The PDS rear shock was also heavily revised internally with a different piston, shims and larger metering needle. These changes addressed some of the harshness riders had criticised on the previous generation. Owners rebuilding the original front end can use the MXOwners fork oil reference when checking service specifications.

The front brake was another important improvement, gaining a revised Brembo system with a two-piston floating caliper and updated master-cylinder hardware. The engine's broad and relatively smooth power delivery remained one of the 250 SX's strongest features, and the MXOwners carburettor reference is useful for owners dealing with worn or modified fuel systems.

At only 95.4 kg dry, the 2009 250 SX remained exceptionally light compared with contemporary four-strokes. It was also increasingly unusual: while several Japanese manufacturers were reducing or abandoning two-stroke motocross development, KTM continued to refine the format. Accurate premix remained essential for reliability, and the MXOwners premix calculator can help prepare the specified 1:60 fuel mixture.