Positioned in Yamaha's classic motorcycle lineup, the 1979 Yamaha RX 125 utilizes a 125 cc (7.6 cu in) air-cooled single cylinder, two-stroke layout. In factory specification, peak output is rated at 13 HP (9.5 kW) at 7,000 rpm while maximum torque reaches 13.3 Nm (9.8 lb-ft) at 7,000 rpm, transferring power to the rear wheel through a 5-speed gearbox and chain final drive. With a specific output of 104 HP per liter, the engine character is reflecting a performance-oriented street tune that balances strong mid-range pull with an energetic top-end rush.
On the scales, the RX 125 measures 96 kg (212 lbs) dry, translating to a power-to-weight ratio of 0.14 HP/kg (7.38 kg per horsepower). Rider ergonomics and chassis geometry center around a 1,240 mm (48.8 in) wheelbase engineered for quick, flickable steering geometry. The 10-liter (2.6 US gal) fuel tank supports practical everyday commuting and weekend road stints.
Specific Output
104 HP/L
Power-to-Weight
0.14 HP/kg (7.38 kg/HP)
Engine
Displacement125.0 ccm (7.63 cubic inches)
Engine TypeSingle cylinder, two-stroke
Engine DetailsSingle cylinder, two-stroke
Power13.0 HP (9.5 kW)) @ 7000 RPM
Torque13.3 Nm (1.4 kgf-m or 9.8 ft.lbs) @ 7000 RPM
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.
Power
Compare engine output with similar motorcycles if acceleration, highway use or two-up riding matters.
Torque
Torque is useful for judging real-world pull, especially for touring, commuting and loaded riding.
Weight
Compare weight carefully because it affects low-speed handling, parking and confidence.
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.
