dmdee99 said:
I also heard that if you use a castor oil you will not be able to use the left over premix that you have from the previous weekend because the oil breaks down and will offer less protection. Is this true???
Not true, I do it all the time with Maxima 927. Maybe harmful if you leave it in below-freezing garage for a couple of weeks. But even at that, I've left model airplane fuel with castor lubricant sit two years in my garage in sealed metal can with no ill effects--but that is alcohol/castor/nitomethane mix, not gasoline/castor.
Also, if you are talking about 927, it is NOT a true pure castor oil mix. According to manufacturer: "Castor 927 is a unique blend of highly refined castor oil, a specially prepared synthetic and an additive system that reduces carbon and gum formation and provides excellent rust & corrosion protection. Castor 927 also contains an exclusive additive that keeps power valves cleaner and working properly." So, it appears it has Castor AND synthetic oil in the mix. I've never had any extra residue or carbon buildup using 927 compared to synthetics I've used.
The beauty--and the problem--with Castor is the much higher flashpoint (for instance, 927 has a 420 flashpoint compared to 240-280 for Maxima synthetics). A lot of people believe this gives you added protection at very high rpm and temps but also leads to the burnt-honey-like residue castor is often associated with. But I love 927 in my bikes. On model airplanes, I run castor in my old iron sleeve engines and synth or synth/castor blend in my newer coated engines.