Your Brison engine has a Nikasil lined cylinder that will take about 50 HOURS of run time to "break in". You DO need to run a petroleum based oil for the first 5 gallons or so, then you can switch to a synthetic. I have a Brison 2.4 (2 of em) a 4.2, 5.8 and two 6.4's. I have never switched to a synthetic oil in any of them. I am using Suzuki CCI petroleum oil at 50:1 in all of them. No problems. Even after 600-700 flights on one of the 6.4's.

Bryan