Oil quality is a major contributor to your engine's performance and life. Always select good quality engine oil. Suzuki recommends the use of suzuki performance 4 motor oil or equivalent engine oil. Use sf/sg or sh/ sj with jaso ma in api (american petroleum institute) classification.

Api: american petroleum institute jaso: japanese automobile standards organization
Sae engine 011 viscosity
Suzuki recommends the use of sae 1 ow-40 engine oil. If sae 10w-40 engine oil is not available, select an alternative according to the following chart.

Jaso T903
The jaso t903 standard is an index to select engine oils for 4- stroke motorcycle and atv engines. Motorcycle and atv engines lubricate clutch and transmission gears with engine oil. Jaso t903 specifies performance requ irements for motorcycle and atv clutches and transmission.
There are two classes, ma and mb. The oil container has following classification for confirming the standard.

Energy conserving
Suzuki does not recommend the use of "energy conserving" oi ls. Some engine oils which is api sh or greater has "energy conserving" indication in api classification doughnut mark.
These oils can affect engine life and clutch performance.
Fuel
Engine coolant solutionSpark plugs
Your motorcycle comes equipped
with ngk cr9e or denso
u27esr-n spark plugs. To determine
if the standard spark plug is
right for your usage, check the
color of the plug's porcelain center
electrode insulator after motorcycle
operation. A light brown
color indicates that the plug is correct.
...
Exhaust control system operation
The excs is operated by the signal supplied from the ecm. The open/close
operation of the excv is performed by
the excva which is controlled by the ecm by changing the current direction of
the actuator motor. The position
sensor (incorporated in the excva) detects the excva movement by measuri ...
Steering components
Steering stem head nut
Steering stem upper bracket
Steering stem lock-nut
Washer
Steering stem nut
Dust seal cover
Dust seal
Steering stem upper bearing
Steering stem lower bearing
Lower seal
Steering stem lower bracket
Steering stem lo ...