here's what i've found. (2000 xc200)
i'm running 50:1 amsoil dominator. 1000-2000 ft elevation. 70 degrees. when it's colder (below 50 degree it needs 1 step richer on main and pilot)
38mm carb is probably too big for the 200. needs more intake velocity to idle better. i had considered building up intake with epoxy, but it's easier to just get a smaller carb so i ordered a 36mm carb, waiting for it to arrive and see if it fixes some idle problems i have.
richer is definitely stronger until it gets horribly rich.
i have #7 slide. br8eg plug, advanced 1 degree from stock.
on my 200, when i jetted by plug reading
42 pilot, 172 main. 3rd position, 1.5 turns out. ddk needle. bike idles great, but is weak on the bottom. plug reads good color.
BUT
when i jet by seat of pants (current jetting):
48 pilot, 175 main, 3rd position 2.5 turns out, ddk needle. is much much stronger from bottom and more responsive bike. plug is black. i ride on the pipe a lot - (like always at top of rev range..) , but i think the black is the pilot. bike pulls hard from the bottom. will pull front end up with ease in first 2 gears (i'm 190lbs...if i lean back it'll pull up in 3rd and if i give it a yank and pull back 4th gear wheelie is possible....)13/52 gearing
48 pilot also smokes a bit, and can load the plug up if i just idle all day - in the tight stuff i'm constantly revving/clutching to keep it clean, which is EXTREMELY annoying during races... smoke cleans up when hot, and on the pipe..
here's the kicker:
bike refuses to idle when hot with 48 pilot. idles great with 42 pilot. but 42 pilot makes bike anemic from the bottom. idle screw has no effect, and i've resorted to lifting slide with throttle adjuster... can get it to idle, but it's almost outta pilot circuit by that point i think...
on advise from les at lt racing :
i'm hoping a 36mm carb will help. #6 or #5 slide will help too. when i get the carb later this week, i'll post my findings.. the other problem i haven't figured out yet is the 36mm carb is possibly 20mm shorter front to back, we'll see if airbox boot will stretch to fit it. also 36mm carb is possibly a bit taller (conflicting measurements at sudco and keihin..) i hope it don't hit the gas tank..