What is the truth about M/C oil?

[Tony W]

I have always used 4T m'cycle oil in my bikes.
The reason being that I did not want to damage the wet clutches
because of additives in "car" oil.
Some very knowledgeable guys swear by "car" oil in their bikes
and say they have no problems.
Are there additives in 4T ( or deleted additives ) that are beneficial
to clutches and gearboxes in bikes ?
Car oil is cheaper and easier to get. Am I paranoid about not using it
or is it a justified decision ?

[Taz]

I use Caltex Delo 400 diesel oil in all my bikes. Works great and is cheaper than a similar spec motorcycle oil. Some people cannot bear the thought of running a "non" motorcycle sprcific oil and that's fine. You gotta be comfortable with ya oil

P.S. The beemer clutch doesn't run in the oil unless you have a buggered output seal

[Bonez]

You gotta be comfortable with ya oil

What he said.

[avgas]

Use motorcycle oil - motorcycles are different from cars and should be treated as such.
What next your gonna run a 190/55 R15 dunop retread on the back cos you picked it up for $50

[Taz]

Use motorcycle oil - motorcycles are different from cars and should be treated as such.
What next? you're going to run a 190/55 R15 dunlop retread on the back because you picked it up for $50

Wot he said....

Where can I get these $50 dunlops??

[Tony W]

P.S. The beemer clutch doesn't run in the oil unless you have a buggered output seal

Shit, no wonder it's not moving !

I DO use car oil in the BMW though.
20W50 in engine, 80w90 in box, shaft, diff.

It's integral box and clutch, eg DR-Z 400, that's more the issue.

I love hard evidence and welcome factual education in this matter.
At the moment it's only ignorance and bigotry that make me use 4T.
Plus the fact that if I use 4T, I can't go wrong.

[Bonez]

I love hard evidence and welcome factual education in this matter. At the moment it's only ignorance and bigotry that make me use 4T. Plus the fact that if I use 4T, I can't go wrong.

You'll find as many varitions/opions/experiences in oil use as there are KBers.

This is going to be a long thread.......................

[R6_kid:Me]

I was told that using 'car' oil in a bike with a wet clutch, more specifically a wet clutch in the same oil as the motor, is a bad idea because the friction reducing additives will make the clutch slip.

[Subike]

I was told that using 'car' oil in a bike with a wet clutch, more specifically a wet clutch in the same oil as the motor, is a bad idea because the friction reducing additives will make the clutch slip.

this is the same as I have read in many MC forums.
I use diesel fleet oil in my yammy, have done now for 6 years.
Oil changes at 5000k regular. The oil comes out almost cleen!
Car oils have additives for internal friction reduction .
Dont work well on a wet clutch

[Bonez]

More specificly avoid any car oils labeled "energy conserving", as the friction modifiers (additive package) are not suitable in a wet clutch application. This has also been mentioned on just about every discussion I've seen regarding oils on M/C forums, KiwiBiker included.

I've been using car oils in my bikes (Duchams, Castrol, Valvoline, Repco branded, etc) for a long time without issue. Changing the oil and filter on a regular basis (least at manufacturers recommented intervals) is the key to engine longivity.