JASO T 903:2016
PERFORMANCE IS GUARANTEED BY
Honda Motor Co. Ltd.
I am a happy owner of a Honda CB350. Here is my take on the engine oil for my steed.
Engine oils
Engine oils are the life blood of an automobile engine.
With out fuel your motorcycle will not run. Without engine oil it will run-for a short distance. Perhaps the last run of the engine.
Engine oil has these vital roles to do inside your motorcycle engine.
Lubrication. Moving parts inside your motorcycle’s engine needs lubrication – to reduce wear and tear and for smooth performance.
Sealing. Engine oil of the correct viscosity maintains the sealing between the cylinder walls and piston rings.
Cleaning. The byproducts of combustion of fuel, the metal debris from the moving metal components etc., if left alone will reduce the life of the engine. Engine oils carry away such harmful deposits and debris, thus keeping the engine clean.
Cooling. As the engine oil passes through the internals of the engine, it absorbs and carries heat away from the engine components.
Protection. The barrier of oil film protects the components of an engine from corrosion.
Wet clutch engines. In wet clutch motorcycle engines, the engine oil does the additional duty of keeping wear and tear off the clutch assembly and the gear box.
Additives.
To perform the above roles efficiently, the engine oil has additives- a typical engine oil will have about 70 percent of base oil and the rest additives.
As the engine runs, engine oil gets contaminated from byproducts of combustion and metal debris. Metal debris are filtered out by the oil filter. Anything small enough to get through the oil filter is kept suspended in the oil. The soot from the burning of fuel is “cleaned” by the detergents and kept suspended in the oil. Anti foaming additives prevent the oil from bubbling at high temperatures.
Formulation of engine oils
To meet the above requirements, engine oils are formulated with a base oil in which polymers for the viscosity and additives to enhance the properties of cleaning, protection from corrosion, to keep the dirt/soot from combustion suspended in the oil and friction modifiers (this one is for not wet clutch engines)
Base oils
Mineral base: Made from petroleum. Most affordable. Good lubrication and with the required additives, will protect the engine. Major drawback is the breakdown in “extreme” conditions. Shorter drain intervals
Semi Synthetic : Blend of Mineral and Synthetic. Hs some qualities of synthetic oils while cheaper than fully synthetic ones.
Synthetic: Synthesized in a laboratory. Has uniform molecular structure. Performs better under “extreme” temperatures. Longer drain intervals.
Viscosity
Viscosity is the thickness of the oil at a particular temperature In hot summers we need thicker oil i.e. oils of higher viscosity. In winter and for cold starts we need thinner oils – lower viscosity
The oil must be thin enough to circulate fast while starting and must reach the optimum viscosity when the engine reaches its operating temperature.
A smooth-running motorcycle needs:
Regular oil changes. Oil must be changed at regular intervals since it gets contaminated and the additives get depleted.
Changing the oil filter. The filter will become clogged over a few thousand kilometres will no longer be able to do its job
The above two makes sure that the engine runs smooth and the life of the engine is extended to the maximum.
Oil Analysis
The only and scientific way is to do an oil analysis. A big NO to the sales pitch of a “snake oil” seller, “YouTube” guru or a “social media” professor.
How often one has to change the oil? Or for how many kilometers the bike can run before the engine oil becomes contaminated and the additives used up to warrant an oil change?
Send a sample from your engine to a designated laboratory for analysis and get their report. Based on that report you can either change the oil or continue using it- well, till the next test. If you change to another brand of oil, and since every brand has different level and composition of additives in their oil, you may have to do this test again. These tests need to be done at regular intervals-say every 1000 kilometers, and these tests are expensive. Hence the ….
OEM engine oil
These engine oils are formulated to meet the specific requirements of the motorcycles manufactured by Honda,
My option – Pro Honda Fully Synthetic Oil 10W30 MA honda2wheelersindia Title

Under the authority of:
ENEOS Corporation, Japan
Specially Developed for
Honda Motorcycle and Scooter India Pvt. Ltd.
These engine oils are formulated to meet the specific requirements of the motorcycles manufactured by Honda, to ensure optimal performance and protection for their engines.

Honda, obviously, must have invested millions in lab tests to finalize these formulations. Why should I go for anything else, when the OEM has done all the required tests and gives me tried and tested products, specifically formulated to perform in their engines to ensure engine performance, efficiency and longevity?

Hence, for me, the choice is obvious. I have the best engine oil for my CB 350 from the manufacturer- Honda. Since I have great faith in Honda, I do not need any of the aftermarket engine oils. Period.
Happy riding
BTW read this disclaimer.