[northwind]

Excellent guide that...

Myself, I reckon the needle shimming mod is a bit of a bodge. It's usually used to iron out a lean spot at around 5000-6000rpm. That spot there, though it's mainly controllde by the needles, is also heavily affected by the jets- too small jets starves the needle circuit. The mod's a way to fix this without buying new parts (well, other than some washers) but for most folks going up a jet size would make more sense, in my experience.