The book says Yamalube 4 10W30 or 20W40, but no mention of type. Yam do mineral, semi-synth & full synth. and unfortunately, their prices are rather "imaginative".
Yam don't make oils, so what are their oils exactly?
I know about avoiding many car oils, because of friction reducing additives & clutch slip, but my local dealer said he recently serviced a VS 1100 for a customer, used their stock, branded motorcycle specific oil (don't remember the brand) and the customer came back complaining of clutch slip. In my previous 2 machines, Suzuki Katana 650 and Bonneville 850, I used Unipart semi-synth and had no problems, but the clutch slip phenomena seems to be a trait of V Stars & Viragos as I understand things.
Advice from long term V Star owners appreciated.