At the heart of the 2025 Yamaha Yz125 cross - motocross motorcycle, Yamaha relies on a 125 cc (7.6 cu in) liquid-cooled single cylinder, two-stroke powerplant. Internal engine geometry specifies a bore and stroke of 54.0 x 54.5 mm (2.1 x 2.1 inches) with a 10.1:1 compression ratio.
On the scales, the Yz125 measures 94.8 kg (209 lbs) wet (curb). Rider ergonomics and chassis geometry center around a 980 mm (38.6 in) seat height — reflecting a long-travel chassis stance that favors ground clearance and off-pavement control, combined with a 1,445 mm (56.9 in) wheelbase engineered for balanced agility and highway composure. The 6.81-liter (1.8 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.
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.
