I was wondering if it's safe to use afterrun oil in the YS motors. I've heard conflicting stories, with most people saying no because it will ruin some diaphram within the engine. I have a .63, and a .45 2 stroke. I'd like to make sure I'm taking good care of them, as they were both pricey motors. Also, I'm getting 14750 RPM with the .45 on a Macs tuned pipe with a 10x6 prop and 20/20. Is that the max RPM it will run?