The difference between car and motocycle oil.

[Lennie]

Can you breifly tell me the difference between these oils and why people should not use car oil in a bike or bike oil in a car if they grade of oil (eg 10w40) was correct?

Thanks.

http://www.opieoils.co.uk/p-812-silkolene-pro-4-10w-40-full-synthetic-ester-4-stroke-engine-oil-for-all-high-performance-motorcycles.aspx

http://www.opieoils.co.uk/p-1146-silkolene-pro-s-5w-40-ester-synthetic-oil-for-high-performance-engines.aspx

[jj205mi16]

car oils have additives (spelling??) in them to make the oil slippy etc. bike oils do not due to them having a wet clutch. so you cant run car oils in bikes, although i work in a bike shop and have always used bike oil in my car with no problems.



just realised this wasn't meant for me to answer , sorry

[Lennie]

Feel free to answer, any info is great.

[mandelbug]

I thought the other difference was that bike oil is burned (forgive me on this, it might just be old bikes) as part of the fuel mixture on 2-strokes

[jj205mi16]

your right enough on 2 strokes mate but you get 4 stroke bikes aswell.

[tallpaul]

I believe its a combination of 2 things, bikes use the same oil for gearbox & top end, so it must be able to resist "shearing/chopping" forces and frothing issues with air being mixed into it. Also a lot of bikes have wet clutches, so some anti-friction modifiers can cause problems.
Saying all that, I know plenty of people who run normal car mineral oil in their bikes without problems, but I ran it in one of mine and the clutch slipped- may have been a coincidence, the bike had done plenty of miles, but I never chanced it again!

[obsessed]

car oil in a bike is a no no as it makes the clutch slip. (as said above)