From the Shell web site:

"A high performance castor/synthetic, SAE30 oil for 2-stroke and 4-stroke racing motorcycle engines. Shell Advance Racing M is specifically formulated for highly stress conditions experienced in speedway motorcycles and go-karts burning alcohol/methanol fuel mixtures. The castor/synthetic blend ensures longer life than a straight castor oil. It can also be used in separate 2-stroke and 4-stroke race gearboxes. Available in 1 litre and 4 litre."

i also rang the Shell tech dept (1300 134 205) and they gave me the castor/sythetic %'s and asured me it will mix, any way i've ordered a liter so i'll know soon, if it dosent i'll just use it for the jetski or trail bike