ORIGINAL: m.gramling
When I was running my YS63 w/ a 14x4W on mine I was getting somewhere in the low 10,000 mark. I don't remember exactly though.
That's what I was getting when I leaned it out to max but my engine only has a gallon through it so I put it back rich. Also I noticed leaning it out for high end made the low end transition bad. So I ended up tuning the high end needle to make a good transition. Until the engine is broken in more, I need to keep it rich. I'm getting about 9500 RPM right now. I think maybe I should switch back to the 13-4W until it's broken in better.