Hmm I have always used castor 927. Breakin regularly use never had any problems. I was using yamalube but found the castor cheaper and just went with it. Heck I used it in my yz125 that i raced nationals on and in my long rod cr 125 that i raced locals with. Not saying the info isn't true just that i have never noticed a difference. What I have noticed a difference on is is the ratio mix. Too little oil and too rich fuel has turned pistons blue and gold. To rich oil and to little fuel equals spooge and fouled plugs. I wonder what the make up is on the jetski 2 stroke oil dont they have there own spec they have to meet tcf12 or something along those lines. Wonder if it dino or syn. Skis seem to run quite along time when properly maintained. But I guess the same can be said for just about anything.