And for the other eye heat a 3/4" drill bit chucked up in an air drill ...
I can get BS34's to almost work on the 998-1100 with one serious caveat . They will pull hard with the throttle arbitrarily pinned OR they will mix fuel cleanly at part throttle cruise . Pick one I don't know how to give you both . Mark Dobeck (DynoJet)and I went back and forth for most of a summer getting several of my customers bikes and my 998 urban terror two wheeler running right . The customers are probably still pissed even though I neither recommended nor supplied this serious impediment to performance . In the end I knew neither was right (thanx for the flash runs Ron !) But the one that was the best and closest to right got me the most grief . That guy thinks I'm an idiot and in ten years hasn't wasted an opportunity to say so . Funny that the last two guys to touch it asked how I was able to get it so close . The one that isn't so good , that guy thinks I'm magic .
just a partial list
various attempts at
springs
needles
needle jets with and without discharge shields
pilots
mains
main air bleed
air horns within the air filters
closer to or further away from the head
adjustable cam sprockets
different headers ....
All because in one case the owner wanted to look like all the other cool kids
and the other thought it was a pain to get the carbs in and out with the stock aribox
Coincidently both of these mental midgets went from 35-36 mpg to 30-31mpg and might have gained a couple of hp on top at the expense of having me spend untold hours filling a huge hole around 4k .
So I was asked recently if I would jet another BS34 set for "pods" ( is it that hard to say individual air filters ? really?) good thing I kept my notes .
Would I jet a BS34 equipped XS650 for individual air filters ? Sure I would . With an eddy current dyno and by the hour ...
Look , I'm not being a dick . It's my experience . Yours may differ but mine was acquired through decades of trial , error , experiment and failure .
It really comes down to clean , direct air flow to the upper opening in the inlet bell of the carb and a consistent flow to the air bleed , also located in the inlet bell . With even a large individual air filter fitted as well as either a molded in inlet bell mouth or a velocity stack placed inside the air filter something fundamental is missing. A single , a pair , a quad , all need a common plenum volume for the "CV" carb to draw on . A straight slide carb is a whole different book let alone chapter that is fortunately well covered in the tech section here .
~kop