Suzuki Boulevard S40

Manufactured and marketed as the Savage from 1986 to 2004, the motorcycle was renamed for model year 2005 as the Boulevard S40. The LS650 has remained unchanged except for minor cosmetic changes, receiving a 5 rather than 4 speed transmission in 1993. With a weight of , Suzuki markets the S40 as "an entry level model to the cruiser line." With a seat height of 28 inches and flatter handlebar, the bike is suitable for shorter riders.

The LS650 Savage was the first cruiser manufactured by Suzuki in 1986. The Kawasaki Vulcan 400 entry level cruiser with a V twin engine was introduced the same year as the Suzuki Savage, and the Vulcan 500 LTD with a parallel twin engine was introduced in 1990. One of the few small cruiser motorcycles available with a shaft drive as an alternative to either chain or belt final drive, the Yamaha Virago 535 was introduced in 1987. Honda launched the Shadow VLX, with a 583 cc V twin for the 1988 model year to compete with the single cylinder Savage. The Savage's persona was a bike that stayed out of harm's way, with a torquey engine (although underpowered for its displacement) that made few demands on the rider. Compared to the discontinued Buell Blast, which had a 30 c. i. d. single cylinder engine with somewhat heavier vibration, the S40 is a more versatile and less expensive entry level motorcycle. Two enduring competitors are motorcycles with air cooled single cylinder engines that have been in production even longer than Suzuki's S40: Royal Enfield's Bullet, and Yamaha's SR400. The latter was reintroduced to markets outside of Japan in 2014.

The Boulevard 40's engine is a 40 c. i. d. (652 cc), four stroke, air cooled, single overhead camshaft power plant, incorporating a Twin Swirl Combustion Chamber (TSCC) cylinder head design first used in the Suzuki GSX series motorcycle engines. This engine features a balance shaft and an output of 31 horsepower. At 60 mph the engine is spinning at a moderate 3940RPM. In 1996 Motorcycle Consumer News measured 31 horsepower at the rear wheel of an LS650 Savage, and a rear wheel torque of 30.5 pound foot. The LS650 registered a quarter mile time of 15.3 seconds at a speed of 81.1 mph, and an average fuel mileage of 55 mpg. In a 2006 road test, Motorcycle Cruiser magazine recorded a quarter mile time of 16.35 sec at 77.2 mph. Average fuel mileage for the S40 was 52.9 mpg. The S40's "thumper" engine (single cylinder, four stroke), is among the largest displacement single cylinder motorcycle engines in production as of 2018, alongside the Suzuki DR650SE and KTM 690 Duke.