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 solutionFront brake master cylinder components
Reservoir cap
Plate
Diaphragm
Reservoir tank
Master cylinder
Dust boot
Piston set
Brake lever
Brake lever pivot bolt
Brake lever pivot bolt lock-nut
Brake light switch
Brake hose union bolt
Brake hose
23 N·m (2.3 Kgf-m,
...
Crankcase breather (pcv) cover inspection
Inspect the crankcase breather (pcv) cover in the
following procedures:
remove the crankcase breather (pcv) cover. Refer to “crankcase breather
(pcv) hose / reed valve / cover removal and installation” .
Inspect the crankcase breather (pcv) cover for
carbon deposit. If carbon ...
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 ...