I live in Spokane WA, elevation between 1200 and 1500 ft. Ours ran really fat and thus felt flat many times when I first had it running on new stock sized jets. I ended up jetting is down 3 steps on the main (I went 1 at a time) and if memory serves me correct, dropped the needle 1 clip. It sure woke the bike up and mileage increased dramatically.
After the jetting is doesn't smoke much at all even under full throttle. You know its a 2 stroke but there isn't the trailing cloud of smoke.
What jets are in it?