I'm just wondering WHY you would want to use any oil other than that specified by Triumph ?
Especially while under warranty - if your engine were to go BANG,
you might be giving Triumph a reason to deny any warranty claim,
as the motorcycle would not have been maintained in accordance with their specifications

If it's because you have a large quantity of it available to you that you don't use for anything else,
my advice would be to sell it, and use the Cash to buy the proper stuff

