When the air is colder and denser should you have to rejet. The only reason I ask is, since it has gotten cold here in the Mid-West my pipe has a lot of black soot on it. Its also all over the grab bar. Like its running rich. It still runs like a stripped a$$ ape. But can it need a tune up on the jetting?

 

Actually it's running leaner. You're right about the density, cold = more dense and more dense equals more oxygen, so you need more fuel. The soot might be a difference in the fuel blend you get for winter, I'm just guessing. Maybe it's got some additives that it doesn't have in the warmer months.