Oil viscosity

[John Hopkins]

This answer is not based on personal qualifications but on knowledge obtained from others over years, so there are things I don't know..

Oil viscosity is the thickness of the oil..

Multigrade oil is oil that changes it's thickness according to temperature..

water cooled motorcycles usually have narrower oilways than air cooled motorcycles, therefore a watercooled engine will need a lower viscosity than an air cooled engine.

The first number in multigrade oils is the thickness of the oil when it is at local temperature, so for very hot countries 15 or even 20..for cold countries 10 or even 5..

The second number is the running thickness at the engine temperature so fo water cooled engines 40 or sometimes 45 and for air cooled engines up to 50..

Now we come to the interesting part, there are two standards agencies...The API (American Petroleum Institute) and the JASO (Japanese Automobile Standards Organization) and most oil is marked with these ratings..The API does not have a specific rating for motorcycles..Probably because Harleys run on almost any oil.. but because of the wet clutch in most other motorcycles including Drifters, we need a special oil with a JASO rating of MA or MA2..

Thats me just about tapped out and if anyone thinks I am wrong please feel free to chime in.

John.

[Anti-hero]

Well I used 10 50w or something like that on my drifter but I know there's like 10 40w and such what's the difference in using either? Ones thicker for colder weather? Or it gives better performance?

[Troll]

how much do you really want to know?
http://en.wikipedia.org/wiki/Viscosity
http://en.wikipedia.org/wiki/Motor_oil

[Anti-hero]

I know the drifter has a few recomeneded oil viscosities
And some are thicker than others... But what really is the difference?