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 solutionStarter motor inspection
Refer to “starter motor disassembly and assembly” .
Carbon brush
Inspect the carbon brushes for abnormal wear, cracks or
smoothness in the brush holder.
If either carbon brush is defective, replace the brush
holder set with a new one.
Measure the length “a” of the carbon brushes using a
v ...
Crankcase emission control system
description
The engine is equipped with a pcv system to prevent discharging crankcase
emissions into the atmosphere. Blow-by
gas in the engine is constantly drawn into the crankcase, which is returned to
the combustion chamber through the
pcv (breather) hose, air cleaner and throttle body.
...
Procedure for returning
to service
Clean the entire motorcycle.
Remove the oily rags from the
air cleaner intake and muffler
outlet.
Drain all the engine oil. Install
a new oil filter and fill the
engine with fresh oil as outlined
in this manual.
Remove the spark plugs. Turn
the engine a few tim ...