RE: Evolution engine, Need commend
Yeah, when I say high speed or high end, I mean the needle valve. On the Evo engine, it has a stop that limits it's travel. I have seen days where the weather was such that the stops were too limiting, and the engine would run better if the stop was overriden.
On the low end, it's a simular situation, the Evo engine has a stop that prevents adjustment of the mixture beyond a certain point. I haven't seen that one be off too much, but it could be.
On an engine with out the stops or limiters that the Evo has, the needle is the high speed needle or mixture, and the low end is usually a small screw that moves something inside the carb to adjust the low end mixture. It's sometimes called a low speed needle, though in many carbs it's not actually a tapered needle like the high end.
I hope that helps.