2021 Yamaha YZ250FX Dyno Test

How much power does Yamaha’s 250 four-stroke cross-country bike make?

Video By: Alec Dare

Since 2015, Yamaha has offered a cross-country version of its 250cc four-stroke motocross bike called the YZ250FX. Last year, the off-road competition model enjoyed a slew of updates that the MX-focused machine received the year prior. We came away impressed with the 2020 YZ250FX’s performance while testing it at Randy Hawkins’ private ranch in Union, South Carolina, which provided some true Grand National Cross Country (GNCC)-like racing conditions.

The YZ250FX’s only changes for 2021 are cosmetic but we are fine with that, not only because of how much we liked the bike last year, but also because we’ll get to test it at our regular test grounds in conditions we are more familiar with this year. After mounting a Dunlop D404 street tire on the rear wheel and conducting multiple pulls on our in-house Dynojet 250i rear-wheel dynamometer, we documented peak figures of 37.8 hp at 12,200 rpm and 18.3 pound-feet of torque at 8,400 rpm.

2021 Yamaha YZ250FX Dyno Chart

2021 Yamaha YZ250FX Engine Specifications

Engine Type: DOHC, liquid-cooled, four-stroke single-cylinder; 4 valves/cyl.
Displacement: 250cc
Bore x Stroke: 77.0 x 53.6mm
Compression Ratio: 13.8:1
Fuel Delivery: Electronic fuel injection