Pe, told me my .61 could be considered broken in when it wouild hold max rpm for longer than 30 seconds, it took three 16oz tanks of 5% nitro fuel to get to that point now it will hold a steady 9,700 with the APC 14x6 and 8,460 with a 12x8 Graupner three blade. The Diesel head is on but not run yet. I'm going to try and get the 7mm MVVS carb to run as a Diesel. The last two 16oz tanks were run at 6,000 rpm and above with several one minute runs at full throttle. The front bearing drips about one drop per minute at full throttle none at any other setting.