DONT even think about it.
blasters can run hot, especially with poor tuning and riding hard. castor based oils gum up at high temps sticking your rings.
hmmm i heard yamaha oils are a dirty junky oil idk tho
Well before switching to amsoil, I used yamalub r for thounsands of miles and it performed well.
Most of my races were in desert heat and 150 to 250 miles with at least 100 miles of prerunning the day before.......... and mostly wfo....