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 solutionSpecial tools and equipment
Recommended service material
Note
required service material is also described in the following.
“Front fork components”
Special tool
...
Engine bottom side disassembly
Note
the crankcase must be separated to service
the crankshaft and conrod.
Remove the engine assembly from the frame. Refer to “engine assembly
removal” .
Remove the engine top side (1). Refer to “engine top side disassembly”
.
Crankcase breather (pcv) cover
R ...
Noise emission control system description
Tampering with the noise control system prohibited: local law or federal law
prohibits the following
acts or the causing thereof:
the removal or rendering inoperative by any person, other than for
purposes of maintenance, repair or
replacement, of any device or element of design in ...