2005 Yamaha YZ 125 Technical Analysis & Specification Breakdown
Built around Yamaha's cross - motocross motorcycle platform, the 2005 Yamaha YZ 125 pairs a 124 cc (7.6 cu in) liquid-cooled single cylinder, two-stroke architecture with road-focused gearing. Internal engine geometry specifies a bore and stroke of 54.0 x 54.5 mm (2.1 x 2.1 inches) with a 8.7:1 compression ratio.
Rider ergonomics and chassis geometry center around a 993 mm (39.1 in) seat height — reflecting a long-travel chassis stance that favors ground clearance and off-pavement control, combined with a 1,486 mm (58.5 in) wheelbase engineered for balanced agility and highway composure. The 7.94-liter (2.1 US gal) fuel tank supports practical everyday commuting and weekend road stints.
Within MotoLibrary's Yamaha archive, this model family spans 5 indexed model years from 2002 to 2007, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.
Standover Height
993 mm (39.1 in)
Engine
Displacement124.0 ccm (7.57 cubic inches)
Engine TypeSingle cylinder, two-stroke
Engine DetailsSingle cylinder, two-stroke
Compression8.7:1
Bore x Stroke54.0 x 54.5 mm (2.1 x 2.1 inches)
Valves/Cylinder1
Fuel SystemCarburettor
CoolingLiquid
Transmission
Gearbox5-speed
Final DriveChain (final drive)
Chassis
Rake27.1°
Front Suspension48mm Kayaba inverted cartridge fork w/adjustable compression and rebound damping
Front Travel300 mm (11.8 inches)
Rear SuspensionKayaba single shock w/adjustable preload, compression and rebound damping and separate hi/lo-speed compression adjusters
Rear Travel315 mm (12.4 inches)
Wheelbase1486 mm (58.5 inches)
Ground Clearance401 mm (15.8 inches)
Wheels & Brakes
Front Tyre80/80-21
Rear Tyre100/90-19
Front BrakesSingle disc
Front Brake Ø250 mm (9.8 inches)
Rear BrakesSingle disc
Rear Brake Ø245 mm (9.6 inches)
Dimensions & Weight
Seat Height993 mm (39.1 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.
