Yamalube or Amsoil?

the blaster gets hotter than the usual two stroke as its air cooled..

Castor based oils maintain their film strength at these temperatures better then almost all synthetics (I'd say all but I cant lol), so Shell racing M, Klotz and Castrol R40..

castor based oils tend to leave more residue behind, but its not a major issue..

You may get better response with a synthetic like Motul 800, or the Amsoil but for longevity I'd use a castor based oil..

racing karts that hit 22,000 rpm; they use castor based oils...
 
Yamalube is a castor based oil.

I run Yamalube 2R cause I premix. Most guys who run it havent really ever had any issues with it. Yamaha knows what theyre doing with engines. I know I dont know more than their engineers do, so I just run what they recommend.

Oil preference is dime a dozen. Unless you actually did a scientific control test, using the same damn engine, or 2 engines built to exact spec, ridden by riders of the same weight, and ridden the same exact trail, in the same way, both with different oils. Log the same amount of time on both of them, and then tear them both down and look at it.

This is the same ages old debate as what oil you put in your car.

Everyone has an opinion, most of them were given to them by whomever got them into riding a 2stroke, and theyve stuck with it because thats what "works" for them.

Youre going to get a bunch of opinions on oils. Youll find people who have had failures with brand x in their quad, and youll find people who have never had an issue with brand x (brand x could be ANY of them, and ALL of them)

You just gotta pick one, go with it, and mix it correctly.