2001 Yamaha YZ250

2001 Yamaha YZ250 – Refining Yamaha’s Proven Two-Stroke Motocross Package

The 2001 Yamaha YZ250 was primarily an evolutionary development of Yamaha’s established 250cc two-stroke motocross platform rather than an entirely new generation. By this stage Yamaha had a highly competitive package, so the focus was on refinement rather than replacing the basic formula. The result was a light, powerful and relatively straightforward competition motorcycle that represents an important period in the development of the long-running YZ250.

Power came from Yamaha’s liquid-cooled 249cc single-cylinder two-stroke, using a 66.4 mm bore and 72.0 mm stroke. A Keihin PWK38S carburettor supplied the fuel mixture, while Yamaha’s exhaust power-valve system helped broaden the usable power delivery. Carburettor condition and setup remain important on surviving bikes, particularly after exhaust, engine or fuel changes. Owners working through jetting or worn fuel-system components can refer to the MXOwners carburettor information and replacement options.

The steel semi-double-cradle chassis was matched with long-travel competition suspension, including approximately 300 mm of front travel and 315 mm at the rear. On a motorcycle now more than two decades old, fork oil condition, seals, bushings and linkage bearings can have a major effect on handling. Owners servicing the front suspension can use the MXOwners fork oil level reference when checking available fork information.

The YZ250 used the familiar motocross combination of a 21-inch front wheel and 19-inch rear, with 80/100-21 and 110/90-19 tyres. Riders replacing aged or unavailable original tyres can compare suitable dimensions with the MXOwners motorcycle tyre size guide.

Regular maintenance remains essential. The NGK BR8EG spark plug, clean oiled-foam air filter, fresh gearbox oil and correctly prepared premix all contribute to reliability. Owners preparing two-stroke fuel can use the MXOwners two-stroke premix calculator to calculate oil quantities for different fuel volumes and mixing ratios.

The 2001 YZ250 did not need to be a radical redesign to be significant. It represented Yamaha refining an already successful competition motorcycle before the larger developments that followed. Its strong two-stroke engine, simple mechanical layout and capable chassis continue to make it an appealing machine for riders, restorers and owners who value the character of Yamaha’s steel-frame YZ era.