I've been using Smith and Allen MA2 10w40 semi-synthetic in my 99 for a couple of years now.Excellent oil and zero problems. I get a full Gallon/5 litres delivered to my door for around £19. Enough to do two oil changes
https://www.smithandallan.com/produc...otorcycle-oil/
I add half a teaspoon of high concentrate MSo2 mixed into half a litre of the oil before I start adding to the engine.
HTH