In between oil changes on my old Z1000 I would drain the oil, fill the crankcase up with diesel, run the motor for two or three minutes on idle, then drain the diesel and whatever else it brought with it, then change the oil filter and put new oil in, that motor gave me over 150000 kms on it and never missed a beat apart from the alternator fucking out on a ride from Perth to Adelaide in the middle of nowhere at night in a thunderstorm, was interesting riding I can tell you. I did the first 88000 kms in 8 months! Just could not break the thing and fuck me me I tried!