This could easily turn into a "which oil" thread, so here goes... I'm a believer in using dedicated chain lube. It gets under the rollers (& everywhere else). I go by looks as to when to apply. I got 38K out of my 140 BHP sport bike chain, 34K on the DL650 (it sees more dirt). Others report similar results with WD-40, but that's more of a solvent. Proof that chains are way better now. Lost's chain lube discussions out there, I've said my piece, I'll shut up now.