2010 Yamaha YZ250

2010 Yamaha YZ250: Almost Completely Unchanged and Still Going Strong

The 2010 Yamaha YZ250 was firmly a minor-update model. In mechanical terms it was essentially the same motorcycle as the 2009 version, with Yamaha limiting the year's visible changes largely to graphics. By this stage the YZ250 platform had already settled into the combination that would make it one of the longest-lived motocross bikes in production: a 249 cc two-stroke engine, aluminium frame and KYB Speed Sensitive System suspension.

The engine retained its 66.4 x 72.0 mm bore and stroke, reed-valve induction, Yamaha Power Valve System and 38 mm Keihin PWK carburettor. Its broad power delivery and relatively simple mechanical layout remained a major attraction for riders who preferred the character and maintenance simplicity of a two-stroke. Owners maintaining the carburettor can use the MXOwners carburettor reference when checking replacement and service options.

Suspension remained one of the YZ250's strongest features. The 48 mm KYB SSS fork provided 300 mm of travel, while the link-type Monocross rear suspension offered 315 mm. Correct oil quantity and damping setup make a major difference to these forks, and the MXOwners fork oil reference is useful when servicing the front end.

Yamaha continued to specify a 30:1 premix ratio using Yamalube 2-R or an equivalent racing two-stroke oil. The MXOwners premix calculator can help owners prepare accurate fuel mixtures, while the gearbox uses its own separate 10W-40 oil supply.

The significance of the 2010 YZ250 is really its continuity. While much of the motocross market had shifted heavily toward four-strokes, Yamaha chose to keep the proven YZ250 in production alongside the YZ250F. That decision gave two-stroke riders a factory-supported Japanese 250 at a time when several competing models had already disappeared.