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 solutionTire inspection
Inspect tire
every 6 000 km (4 000 miles, 12 months)
Tire tread condition
Operating the motorcycle with excessively worn tires will
decrease riding stability and consequently invite a
dangerous situation. It is highly recommended to replace
a tire when the remaining depth of tire tread reaches ...
Excva pulley inspection
Inspect the excva pulley in the following procedures:
remove the excva pulley. Refer to “excv cable removal and installation”
.
Visually inspect the excva pulley for wear and
damage. If there is anything unusual, replace the
pulley with a new one.
Install the pulle ...
Crankcase breather (pcv) hose / reed
valve / cover removal and installation
Removal
Lift and support the fuel tank with the prop stay.
Refer to “fuel tank removal and installation” in section 1g .
Remove the air cleaner box. Refer to “air cleaner box removal and
installation” in section 1d .
Disconnect the crankcase breather (pcv) hose (1).
...