Engine oil

[Slaninar]

In some engines it can cause clutch slip, although I believe Ducati recommend it for their bikes (dry clutches of course). A good semi-synthetic is all you need, even with hard usage. Or even a good quality mineral oil will probably suffice.

JASO MA, or better JASO MA2 motorcycle specific oil does NOT cause clutch to slip. That is false information.

Semi synth is good enough for most bikes (even though full synth is better in every way, except the price for most bikes).

Mineral oil is not worth the money, but each can choose for themselves.

car oil comes from oil that was laid down 165 million years ago from the decomposing bodys of 4 legged dinosaurs whereas motorcycle oil comes from dinosaurs that had only two legs and that's why it's more expensive?

I have already pointed out differences of regular car engine and a motorcycle one. So apart from marketing and lower production, there is some quality difference.

A lot of people seem to distrust supermarket own brand stuff, but if its 10w40 semi synthetic bike oil, is it any different to the branded stuff??? Im guessing tesco dont have their own oil refinery so they are they not getting it from the same place?????

Look at the standards they comply with.  API SL and JASO MA2 oils tend to be more expensive than those complying to lower standards.

Also, some oils are branded "synthetic", but are really semi-synthetic.