Castrol Power 1 Racing 4T is designed for high performance 4-stroke sports bikes
Trouble is, the 961 ain’t one o’ them!
Comnoz was of course testing oils for the ‘old’ Commando. One really interesting thing he discovered is that old engines place very different demands on oils.
Yes, your 961 might be a new bike, but it’s a seriously old skool engine!
‘Modern’ engines are designed differently, so need a suitable oil.
‘Old’ engines do not manage heat so well, so can ‘cook’ oils. Tolerances tends to be much bigger, so need oils able to handle this. The Harley gearbox is a famously clunky affair, and specialist oils have been designed specifically for this.
Personally, I still intend to use the Bel-Ray gear oil as it was specifically designed for this box.
And I’m thinking the the Bel-Ray 10w 50 would be good in the 961 engine. It had one of the highest load ratings in Comnoz’ tests, being a 10w it should be the same when cold as a 10w 40. But being a 10w 50 should add an extra element of protection on not days, track days, etc.
However, having said all of that, it’s very easy to over worry this topic!
Regular oil changes are probably more important that oil choice.
But... I wouldn’t let the fact that an oil, any oil, is free affect my decision IMHO...