Posts : 585 Join date : 2010-03-16 Age : 89 Location : Milton, WI 53563
Likewise my friend.
I was checking the Super Tiger 2500 manual and as you already knew, they say "no less than 15% lubricant by volume" the blend synthetic / castor is not critical even all castor is ok. Therefore as you mentioned you might add a couple ounces of castor, I believe it would be a excellent idea in a new engine.