when tuning carb should u tune mainjet first or ildemixture?\\

also when turning idle mixture should motorspeed/throttle be on low?

I have always adjusted the main jet first then the idle.
And yes, keep it on a low from, that way you'll hear how the motor responds to any adjustment made.

On low for both?

Darn auto correct goofed up what I was typing...keep it on a high rpm when doing the main jet, and low rpm for the idle. Use the sound of the engine as feedback when tuning the jets, if it doesn't sound right then try a different adjustment.

I agree. I always mark the jet screws with a magic marker on their edges; it makes it easier to keep track of the changes you've made. And opt for a richer mixture in the end by a 1/4 turn on both jets. MH