I just put my air box lid back on (minus snorkel). I've been jetting my brains out for the last year trying to get rid of a bottom end hesitation and/or flat spot when I "wick it" when cruising just off idle. I managed to jet my problem away but have to put up with being a little rich through most of my throttle positions as well as having to clean up the spooge after every ride.
I introduced the idea jokingly of putting my air box lid back on when commenting on another thread. I then started thinking about what would actually happen if I did put it back on...so, this is what I discovered...
I was able to drop whatever needle I was trying 2 clip positions (raise the clip) and finally clean up the rich low to mid throttle positions! I was blown away! I've never been able to run any BEx, CEx, or DEx needle in position 3 without a major hesitation. Position 4 would give me a flat spot to deal with. I tried CEL/3 with decent results (an occasional hiccup and go) and CEK/3 was slightly better in the hiccup department. both were very linear power delivery, but not real powerful down low (read flat power delivery off idle) but clean running. CEL/4 was a little too rich throughout the bottom and mid. I then went with DEK/3 and found the most power and cleanest running combination that I've ever experienced with this bike! No flat spot on the bottom (just good power) and way more power than any Cxx needle I've ever ran. All this with crispy clean jetting throughout the power band. I did my jetting tests with a 152 main, # 7 slide, 42 pilot, AS 1 1/4. I'm running an FMF -35, "Q" silencer, stock carb, Uni filter, and a RAD valve. I was running in the dry desert at 3000' and 82 degrees.
Needless to say I'm keeping the lid on...perminently.