never though about it much, but i just got back from a company that tunes G 230 and 260 engines for the FG 1:5 race cars.
they say to check the piston rings every 20 liters, eeehh sorry, every 5 gallons.
do you ? so far i have put gas in my 22cc zenoah G2D and a new spark plug every spring and that was it.
the tuner is making one 230 and one 260 for me as a sample to testfly in my comeback. he belives that the tuned 230 will do better in my aplication because it runs much smoother. the 260´s have a uneven weight distribution between the piston and the crank and are not as smooth to start out with and need extra balancing.
the 230´s end up with 5.6 Hp and 2.7 Nm torque the 260´s with 3.6 Nm torque. max torque is around 7000 - 8000 rpm. which is fine for me as i can gear up or down to give me max torque at around 1200 rpm on the main rotor.
still raining and stormy outside