Originally Posted by Dakar Dan
I'd recommend staying with the stock set-up with only light mods (snorkel out, drilled slide and raised clip, adjustable air-fuel screw and hex-key carb bolts) in conjunction with the stock pipe as a reliable, economical ride. I also replaced my cable choke with a manual one due to sticking early on, as well as ditching the vacuum petcock when I got an IMS tank. Think of this as an easy "Stage 1" step.
The DynoJet kit is only adequate at addressing some of the stock carb's shortcomings and if you're going to go down the path of fettling, then save your bucks towards the FCR carb. IMHO "Stage 2" mods like this are really still a compromise around the BST-40's CV design.
I pretty much agree with most of what you said. However I would give the BST carb a little more credit. I think with some basic mods as you mentioned, and include a few bucks for a few jets and an adjustable needle (or jet kit if prefered), the stock carb can be made to purr and provide some pretty good bang for the buck. I think some just don't have the patience/desire to keep tinkering with it to get it right. I will certainly agree that it will never have the immediate punch of a pumper carb, but it can make good power and run pretty much flawlessly with some careful tuning. For me it's just not worth the dollars to get a pumper (for now anyway
Main - 142.5
needle - stock (modified/improved taper with one .040 shim)
Slide drilled with second hole (same size as original)
fixed D shelf problem with plastic washer cut to size
No backfire screen
Air box open about twice original hole size
Edit: Thanks 996DL and NordieBoy for posting those jet comparison charts here.