Corresponding with bicycle engines.com today revealed things I did not know. Their customer service is excellent by the way. They sent me a Zeda instruction manual. Premium gasoline was recommended . It also recommends oil to gas of 30:1. 20:1 If you are working the engine hard, operating in hot temperatures, or for break in. The manual suggest Dino oil only and recommends Valveoline racing oil. It warned not to use synthetic or synthetic blend oils because of premature failure of bearings and seals and that use of these oils voids the warranty. And lastly BE recommend 16:1 for Phantom 85. Perhaps everyone knows all this but me. But I thought I would share.