1. Guessing TBS is ThunderBird Sport?, do we have a part #?
Yes, it is Thunderbird Sport. #T1241024
2. Needles effect the carb performance between 1/3 and 2/3 throttle correct? Or between pilot and main?
On this pix, the taper/diameter are detremined by which needle ypou use (TBS/Thruxton). The clip position is the same as shims on ours since they do not have moveable needle clips. Adding shims to the needles will accomplish the same thing. Raising the needle (adding shims makes the carb richer in the areas shown)
3. Advantages/ Disadvantages of needle swap?
It helps to eliminate flat spots at different throttle positions. It works differently for everyone it seems. These carbs are a bit fussy about them.
4. Why TBS over Thruxton?
Thruxton is fatter and therfore a bit richer than the TBS. If you want to speriment with needles, get sets of both, try TBS then Thruxton, use the ones that feel the best for your bike. BUT you usually have to drop mains down a size or two as well.
5. Quick how to?/ What not to do?
Carb shimming - but shows the same stuff.
