ORIGINAL: Crash-RCU
Saito says to use only snythetic oil because of carbon build up from the castor. Most just disregard that and use the sny/castor blend because of superior lube quality of castor.
Those who have had Saito many years to know what they are talking about choosing fuel that does not ruin the engine and how to keep the engine maintenance such as William Robison had spent much time and effort to make Saito engines more reliable.
Read here that you do not have knowledge of the Saito engine and plan to have a Saito engine, it is worth knowing:
http://www.rcuniverse.com/forum/m_5843055/tm.htm [sm=thumbup.gif]