Built around Yamaha's cross - motocross motorcycle platform, the 2011 Yamaha YZ125 features a 124 cc (7.6 cu in) liquid-cooled single cylinder, two-stroke configuration. Internal engine geometry specifies a bore and stroke of 54.0 x 54.5 mm (2.1 x 2.1 inches) with a 8.6:1 compression ratio.
On the scales, the YZ125 measures 94.4 kg (208 lbs) wet (curb). Rider ergonomics and chassis geometry center around a 998 mm (39.3 in) seat height — reflecting a long-travel chassis stance that favors ground clearance and off-pavement control, combined with a 1,443 mm (56.8 in) wheelbase engineered for balanced agility and highway composure. The 7.95-liter (2.1 US gal) fuel tank supports practical everyday commuting and weekend road stints.
Within MotoLibrary's Yamaha archive, this model family spans 19 indexed model years from 2008 to 2026, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.
Standover Height
998 mm (39.3 in)
Engine
Displacement124.0 ccm (7.57 cubic inches)
Engine TypeSingle cylinder, two-stroke
Engine DetailsSingle cylinder, two-stroke
Compression8.6:1
Bore x Stroke54.0 x 54.5 mm (2.1 x 2.1 inches)
Fuel SystemCarburettor. Mikuni TMX 38
IgnitionCDI
LubricationDry sump
CoolingLiquid
Transmission
Gearbox6-speed
Final DriveChain (final drive)
Chassis
Frame TypeAluminium
Front SuspensionSpeed-sensitive system inverted fork
Front Travel300 mm (11.8 inches)
Rear SuspensionFully adjustable single shock
Rear Travel315 mm (12.4 inches)
Wheelbase1443 mm (56.8 inches)
Ground Clearance386 mm (15.2 inches)
Wheels & Brakes
Front Tyre80/100-M21
Rear Tyre100/90-M19
Front BrakesSingle disc. Wave
Front Brake Ø250 mm (9.8 inches)
Rear BrakesSingle disc. Wave
Rear Brake Ø245 mm (9.6 inches)
Dimensions & Weight
Weight incl.94.4 kg (208.0 pounds)
Seat Height998 mm (39.3 inches) If adjustable, lowest setting.
Use this page to compare this motorcycle by its real specifications, not only by model name. Focus on the details that affect fit, comfort, handling, range and ownership.
Seat Height
Check the seat height against your inseam and riding posture before choosing a motorcycle.
Fuel Capacity
Fuel capacity helps estimate touring range and how often you may need to stop.
Brakes
Brake setup is worth comparing if you ride in traffic, mountains or with a passenger.
Suspension
Suspension details can matter for comfort, road feel and long-distance riding.
Transmission
Transmission and final drive affect maintenance, smoothness and everyday usability.
