http://www2.towerhobbies.com/cgi-bin...&I=LXS627&P=ML
benol is castor oil, castor oil is the best oil you can get in your fuel, once you build up a layer of "varnish" as some people calle it, it acts as a protective layer like teflon, if you want more details PM Fuelman and he will tell you everything good about castor oil

you can find it at most motorcycle shops where they have dirtbikes/racing carts