Here's from the instructions from my Moki 2.10......

"Moki 2.10 engines have hard chrome cylinders and, therefore, require a modest break-in period. The minimum time is 30 minutes, with best results at 1 hour or more. Make sure that you do not run the engine with a lean mixture during the first 20 - 30 minutes. In fact, it is best to run your engine as rich as possible during the first phases of the break-in procedure. This would be a speed of approximately 6000 RPM with the recommended 20x8 Moki prop. After that, you can lean it out for short periods of time. When the engine will hold a lean setting without slowing, it can be considered broken-in. It is best to use 20% oil, 80 % methanol (FAI) fuel. Small amounts of nitro are OK, but it will make it more difficult to run dependably at the very rich setting without leaving the battery connected. Never attempt to accumulate all of the break-in time in one run. It is always best to run the engine in short runs of 2-3 minutes and let it cool down before starting it again. Do not run at low throttle settings during break-in. Run the engine at full throttle and slow it down by increasing the fuel mixture. Take your time, do it right, and you will have an engine that will last a very long time.

At no time should your Moki engine be operated on straight synthetic oil fuel. Doing so can damage the engine and void your warranty. If castor based fuel is not available, then you must add at least 6 ounces of castor oil (Klotz Bean Oil or equivalent) to each gallon of fuel....."