SR400

2018 Yamaha SR400 Technical Analysis & Specification Breakdown

Positioned in Yamaha's allround motorcycle lineup, the 2018 Yamaha SR400 pairs a 399 cc (24.4 cu in) air-cooled single cylinder, four-stroke architecture with road-focused gearing. In factory specification, peak output is rated at 22.9 HP (16.7 kW) at 6,500 rpm while maximum torque reaches 27.4 Nm (20.2 lb-ft) at 3,000 rpm, transferring power to the rear wheel through a 5-speed gearbox and chain final drive. With a specific output of 57.4 HP per liter and a 3,500 rpm working window between peak torque (3,000 rpm) and peak power (6,500 rpm), the engine character is prioritizing low-RPM tractability, mechanical longevity and relaxed throttle response over peak redline numbers.

On the scales, the SR400 measures 174.2 kg (384 lbs) wet (curb), translating to a power-to-weight ratio of 0.13 HP/kg (7.61 kg per horsepower). Rider ergonomics and chassis geometry center around a 785 mm (30.9 in) seat height — offering a neutral standover height that accommodates most average-inseam riders without sacrificing cornering clearance, combined with a 1,410 mm (55.5 in) wheelbase engineered for quick, flickable steering geometry. The 12.11-liter (3.2 US gal) fuel tank paired with a rated consumption of 3.56 L/100 km provides an estimated theoretical range of roughly 340 km (211 miles) between fill-ups.

Within MotoLibrary's Yamaha archive, this model family spans 6 indexed model years from 2011 to 2019, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.