Yamaha YZ250

The Yamaha YZ250 dates back to 1974 and, unlike the 2-stroke motocross models from other Japanese manufacturers, is still marketed in North America and Europe.

Main competitors:

• Honda CR250R
• Kawasaki KX 250
• Suzuki RM 250

Considering the Yamaha YZ 250 model, it should be noted that the models are of the greatest interest since 2005 - it was at this time that the motorcycle began to be equipped with an aluminum frame.

The model was based on a single-cylinder 2-stroke liquid-cooled engine with a volume of 249 cm³, producing 53 hp. power and 49 Nm of torque (data refer to 2005 model).

In 2006, the Yamaha YZ250 received a new KYB SSS (Speed-Sensitive System) front fork, in 2008 - petal brake discs.

In 2017, the front brake disc diameter is increased from 250 to 270 mm.

Other features of the model include an aluminum frame, the presence of a YPVS power valve system (optimize engine performance depending on engine speed), a carburetor power system (with a throttle position sensor), fully adjustable sports suspensions, an 8-liter fuel tank, a 5-speed gearbox and 103 kg of curb weight.

In parallel, the Yamaha YZ125 version was also produced, which generally had a lot in common with the YZ250, but was equipped with a smaller engine and a 6-speed gearbox.

The Yamaha YZ 250 has taken part in many international motocross competitions, where it consistently ranked high:

• 5 AMA National Motocross
• 9 AMA National Supercross
• AMA National Supercross (2004)
• 6-time AMA National Offroad Championships
• EMX300 Championship (2014)

Also in the line of Yamaha motocross motorcycles there is a 4-stroke version - Yamaha YZ250F.

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Specifications

Specifications Yamaha YZ250 (2005+):

Model	Yamaha YZ250
Motorcycle type	cross
Release year	1974+
Frame	Aluminum half duplex
Engine type	1-cylinder, 2-stroke
Working volume	249 cm³
Bore / stroke	66.4 x 72.0 mm
Compression ratio	8.9 ~ 10.6: 1 9.2 ~ 10.9: 1 - YZ250 (up to 2015, North America)
Cooling	liquid
Number of valves per cylinder	petal valve
Fuel supply system	Carburetor, 1x Keihin PWK38S
Ignition type	CDI
Maximum power	53.0 h.p. (38.9 kW) at 8000 rpm
Maximum torque	49.0 Nm (5.0 kg-m) at 7500 rpm
Gearbox	5-speed
Drive type	chain
Front tire size	80 / 100-21 51M
Rear tire size	110 / 90-19 62M
Front brakes	1 disc, 250mm, 2-piston caliper - YZ250 (up to 2017) Single disc, 270 mm, 2-piston caliper - YZ250 (2017+)
Rear brakes	1 disc, 245 mm, 1-piston caliper
Front suspension	48mm inverted fork (fully adjustable), 300mm travel
Rear suspension	linkage with monoshock (fully adjustable), stroke - 315 mm
Motorcycle length	2184 mm
Motorcycle width	827 mm
Motorcycle height	1309 mm
Wheelbase	1481 mm 1446 mm - YZ250 (2015+)
Saddle height	997 mm 976 mm - YZ250 (2015+)
Minimum ground clearance	385 mm 367 mm - YZ250 (2015+)
Acceleration to 100 km / h
Maximum speed
Fuel tank capacity	8.0 l
Motorcycle weight (curb)	103 kg

Documentation

• Yamaha YZ250