i just switched over to castor 927 from belray H1R on both my bikes. when i went riding today, the guys i were riding with swore i was running race gas, it smells so sweet. that smell is what i used to associate with 2 strokes, its what i always smelt when i went riding in the sand pits on my old quad. im so happy that i finnaly have that smell, kind of wierd, aint it im mixing it a 40:1 now too, i notice it smoking less. H1R oil is much thicker than castor 927, the viscocity is much higher in the castor 927. both my bikes, banshee and cr 80 ran great, so i guess it works!!