I had 3 Saitos and 2 of them needed bearings within 3 months. I sent them back,didnt want to risk further damage with fairly expensive engines. It seemed like they went after switching to 20-30% nitro,I didnt use ARO,hard to put it in right with the carb located in back and inside the cowel. The fuel I used had 20% oil and I always run 'em dry after emptying the tank. After reflecting back into the past,I will give up on the 4-strokers and keep my 2-strks.At least I can fix them myself,quickly,cheaper with after market bearings, but I havent had premature bearing failures with the 2-strks.(OS) I'm going to keep 1 glow(60UCD) and move to gas,plenty to choose from now a days.