10/11/2016
The 2011 Yamaha SR400 is a testament to timeless motorcycle design, offering a blend of classic aesthetics and modern mechanical refinements. While its iconic silhouette has remained largely unchanged for decades, the 2011 model year saw some significant upgrades aimed at improving its performance and environmental compliance. At the heart of this machine lies a robust 399cc engine, a single-cylinder powerhouse that has earned a reputation for its reliability and engaging riding experience. This article delves into the specifics of the 2011 SR400's power output, its engine characteristics, and the other key components that contribute to its enduring appeal.
Engine Power and Torque
The 2011 Yamaha SR400 is propelled by a 399cc, four-stroke, single-cylinder, air-cooled engine. This powerplant, a staple of the SR series, was enhanced for the 2011 model with an electronically controlled fuel injection system. This upgrade was a significant step forward, providing a more responsive throttle and improved fuel efficiency compared to earlier carbureted versions. From the factory, this engine boasts a healthy 23 horsepower, delivered at 6,500 revolutions per minute (rpm). The torque figure stands at 27 Newton-metres (Nm), which is equivalent to approximately 20 lb-ft, achieved at a lower 3,000 rpm. This torque delivery at lower revs means the SR400 offers brisk acceleration from a standstill and a satisfying pull through the gears, making it ideal for city riding and leisurely cruising.
Engine Upgrades for 2011
The 2010 upgrades, which carried over into the 2011 model, were pivotal in keeping the SR400 relevant in an increasingly regulated automotive landscape. The introduction of the new fuel injection system was a key enhancement, offering riders a more precise and immediate throttle response. This system works in conjunction with a larger oxygen sensor, allowing for finer adjustments to the fuel-air mixture, thereby optimising both performance and emissions. Furthermore, a new exhaust system was fitted, complete with a catalytic converter. This was a crucial addition to meet tighter emission standards, ensuring the SR400 could continue to be sold in markets with stringent environmental regulations, all while maintaining its characteristic exhaust note.
Chassis and Handling
The 2011 Yamaha SR400 is built upon a sturdy double-cradle steel frame. This frame design provides a solid foundation for the motorcycle, contributing to its predictable and stable handling. Up front, the SR400 features a telescopic fork with 150 mm of wheel travel. This setup is well-suited for absorbing road imperfections, offering a comfortable ride. At the rear, the motorcycle is equipped with dual side-mounted shock absorbers. These are designed to work in harmony with the frame and front suspension to deliver optimum handling performance, allowing the rider to feel connected to the road and confident in their control.
Braking System
Effective braking is paramount for any motorcycle, and the 2011 Yamaha SR400 is equipped with a capable braking system. The front wheel features a substantial 298 mm disc brake, paired with a hydraulic caliper. This provides strong and progressive stopping power, essential for safe riding in various conditions. At the rear, a traditional drum braking unit is employed. While drum brakes are less common on modern motorcycles, the SR400's rear drum offers reliable stopping performance that is well-matched to the bike's overall power and weight, contributing to its overall balanced braking capability.
Standard Features and Aesthetics
Beyond its mechanical prowess, the 2011 SR400 retains the classic styling that has made it a favourite among enthusiasts. From the factory, the bike comes equipped with a suite of iconic features. A round headlight, housed in a chromed casing, is a prominent visual element, harking back to an era of simpler motorcycle design. The front fender is made of steel, adding to the bike's authentic retro feel. The teardrop-shaped fuel tank is another signature design cue, contributing to the SR400's elegant profile. For rider and passenger comfort, a one-piece dual seat is fitted, complete with a passenger grab rail for added security. The exhaust system is finished in chrome, complementing the bike's overall classic look. Finally, the SR400 rides on wire-spoke wheels with lightweight rims, reinforcing its vintage character and contributing to a more nimble feel.
Comparison with Previous Models
When considering the 2011 Yamaha SR400, it's worth noting its evolution from earlier models. Prior to the 2010 upgrades, SR400s typically featured carburetted engines. While carburettors offer a certain mechanical charm and can be easier for some home mechanics to tune, the fuel injection system on the 2011 model brings significant advantages in terms of fuel economy, emissions control, and throttle response consistency. The addition of the catalytic converter is also a key differentiator, marking a commitment to meeting modern environmental standards. Mechanically, the core of the engine remained similar, but these electronic and emissions-related updates made the 2011 model a more modern and compliant machine.
| Feature | 2011 Yamaha SR400 |
|---|---|
| Engine Capacity | 399cc |
| Engine Type | Four-stroke, single-cylinder, air-cooled |
| Fuel System | Electronic Fuel Injection |
| Horsepower | 23 hp @ 6,500 rpm |
| Torque | 27 Nm (20 lb-ft) @ 3,000 rpm |
| Front Suspension | Telescopic fork, 150mm travel |
| Rear Suspension | Dual shock absorbers |
| Front Brake | 298mm disc |
| Rear Brake | Drum |
| Frame | Double-cradle steel |
| Wheels | Wire-spoke |
Frequently Asked Questions
Q1: What is the horsepower of the 2011 Yamaha SR400?A1: The 2011 Yamaha SR400 produces 23 horsepower at 6,500 rpm. Q2: What type of fuel system does the 2011 SR400 use?A2: It uses an electronically controlled fuel injection system. Q3: What are the main upgrades from previous models?A3: The key upgrades for the 2011 model include a new fuel injection system, a new exhaust system with a catalytic converter, and a larger oxygen sensor. Q4: How does the braking system perform?A4: The SR400 features a 298mm front disc brake with a hydraulic caliper and a rear drum brake, offering solid and reliable stopping power. Q5: Is the 2011 Yamaha SR400 suitable for beginners?A5: Yes, with its manageable power, predictable handling, and comfortable riding position, the 2011 SR400 is often considered a suitable motorcycle for new riders looking for a classic experience. In conclusion, the 2011 Yamaha SR400, with its 23 horsepower engine and torque-rich delivery, offers a charming and capable riding experience. The fuel injection and emission control upgrades from 2010 ensure it meets modern standards while retaining its beloved classic character. Its robust chassis, reliable braking, and iconic styling make it a compelling choice for those who appreciate timeless motorcycle engineering and a truly engaging ride. The emphasis on classic design and mechanical simplicity, combined with these thoughtful upgrades, solidifies the SR400's status as an enduring icon.
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