I forgot to mention in my original reply to Spaceworm more info about oil ratio. So far, in my Saito conversions, I've been using 32:1 non-synthetic Stihl "High Performance" oil, or equivalent. There is no synthetic content in that one. Lately I've been experimenting with HP "Ultra" full synthetic at 50:1 ratio. No conclusions yet, especially since most of my experiments have been on non-Saito 4-strokes. Another option is to try Stihl HP "Super" at around 40:1, but monitor the engine temperature with a non contact probe. The head is about 310F right at the exhaust outlet. The idea is to run an oil and a ratio such that you don't get carbon buildup around the valves. Otherwise, too rich on oil, and the valves will start leaking, losing compression.