How about an 8 year old girl on a sportrak90? I do that.
Plug color can be misleading. Your main could be fine (WOT plug chop color checks) and your needle diameter or clip could still easily hose the bottom end.
If 1.5 to 3.5 turns out on the AS doesn't make a difference, you're most certainly way to rich someplace else.
CDave has an elevation/temp jetting grid chart on his website:
http://justkdx.dirtrider.net
6000' will certainly figure in on your jetting AND your overall performance. It be t-h-i-n up there!
If you're still running the stock needle, try it @ #2 clip (second from blunt end. You would be DROPPING the needle if it's in the middle position now).
Don't wish to oversimplify things. Don't know what you know, what you don't. I'd prefer erring on the side of simplicity.
You're pilot should be down in the 40 range...maybe even a 38 with the -35 pipe and 6000 ft el.
Try a 'G' series plug...like BR8EG. The fine wire helps a LOT on low-end, chugging plug load-up tbls.
Everything else OK, you should be able to (example) chug around with the XR @ 2+ turns out on your AS most of the afternoon, turn it back to 1.25 turns out and get response good enough to pull as hard as you wanna! 1/8 turn on my AS makes a difference way up to 3rd gear pull.
Cheers!!