The Suzuki DRZ400S\SM is a street legal motorcycle that's designed with several nods to the world of dirt bikes. It features a single-cylinder DOHC 4-stroke 398cc liquid-cooled engine that's lubricated via a dry sump system. The 5-speed constant mesh transmission is hooked to a chain with 110 links. This chain is closer to those installed on most of Suzuki's motocross bikes than chains seen on normal street motorcycles. This somewhat unusual combination provides riders with low-RPM torque coupled with a crisp throttle response rate.
The throttle receives help in this department from a patented Mikuni BSR36 CV-type carburetor that gets feed by a 6-liter air intake box. The cover has quick-release fasteners on one side, which makes changing the air filter much easier on the Suzuki DRZ400S\SM than on many previous motorcycles.
While Suzuki DRZ400S\SM owners can exchange parts with the similar Z400S, Suzuki's engineers equipped this ride with an inverted front fork to cut down on unsprung weight while improving overall handling. It also helps to support the automatic decompression system, which translates into faster engine starts. The CDI electronic ignition equipment helps to further cut down on the amount of time it takes to get the engine roaring.
A compact 6.5 amp battery provides riders with plenty of starting power, but Suzuki's technicians hoped to reduce how much maintenance bikers would have to put into the battery by sealing the box it sits in. In order to reduce overheating, they also installed a thermostatically controlled cooling fan on the left radiator. It helps to maintain a consistent operating temperature in normal traffic conditions, which is something that Suzuki's more traditional dirt bikes struggle with.
Forged aluminum pistons further reduce the total weight of the Suzuki DRZ400S\SM, as these are 10 percent lighter than regular cast pistons. While they receive additional oil-cooling through crankcase oil jets, they do eventually necessitate replacement like all parts. They require specific proprietary components when they are replaced as a result of how radically different they are from the pistons on most other comparable bikes. Further savings in the weight department come in the form of a clutch, magneto and valve cover all made from magnesium.