For my YS 63FZ I read the manual. I listened to many good YS owners on this forum. I used the right fuel and plug. I tuned the high end needle to give me the best transition and didn't touch anything else. I never run it lean. I know I could play with it more but it runs great. It may not make sense to some people to tune the high end needle for the fastest transition but it's simple and it works.

I really should lean out the low end a little one of these days.

Awesome engine. Pressurized fuel systems are the best.