Tango, forgive the daft question from me a new lad but do they state on the bottle if they contain those additives? I have not had to change my oil yet but if I use oil that is specifically advertised as being for bikes, will it not contain additives? man it can get so confusing! Cheers I think one of the main culprits is that Magnatec oil.....but I think others have had problems with some different oils too. Oil designed specifically for use in bikes should not have any additives in that would affect the clutch as most bikes use a wet clutch. The only question then really, is whether to use fully synthetic or semi synthetic. ..... ] Thanks man.. Oh dear synthetic? fully synthetic? Yet more confusion... I think my man at the bike shop said to use semi synthetic... Anyway, I am off to research this now, sorry for being a pain asking stuff but I do appreciate the help