how to choose a phbh atomiser

[olliewtf]

hello all,
going through the motions jetting my bike in.
I am curious to know however, how people go about selecting their atomisers.
Im running a phbh 28mm delly on a suzuki conversion with high port timings and 60mm crank, so about 195cc, with a jl3 and auto advance reedspeed cdi.
now i understand that there is essentially a choice of 3, av264/6/8.
I also understand that there is a selection of needles, x2/7/13 etc.
now i get that with needle selection you can easily work out whether to go up or down, as if youre on highest clip and still rich you can pick the next leanest needle and vice versa.
But I am confused as to the relationship between this and the atomiser.
I understand that the atomiser is what meters the amount of fuel that the needle taper can supply, so is it a case of, if im in the richest needle setting on an av264 atomiser i should move up to av266 on the leanest needle?
im pretty sure thats not the case.
either way av264 and x7 is too lean for my set up, which is what i expected. im going to try av266 and x7 next.
But i would sure love to understand the relationship far better.
all help appreciated!

[B-Race Tuning]

That's pretty much it Ollie. I usually start the other way round, rich to start then lean off but same principle, once reached the leanest needle position, go down an atomiser and go back to richest on the needle.
Your choice is many, many more than the 3, but you will end up in the range of those three (AV266T2?).
Oh, and although unlikely to be needed, don't forget the AS' or they'll feel left out.

[olliewtf]

ahhhhh, cheers b-race, thats cleared up ALOT of confusion. In which case its definitely worth having more needles at my disposal. But goddamn! those jets are pricey
I am aware that there are loads more options, but just trying to keep it simple!
AS atomisers, are leaner are they not? more commonly used in smaller ph carbs?
thanks again mate.

[paul213]

if you have an as atomiser in the size you want an av in you can just shorten them

[Special X]

AVs are great for racing as they run very rich at lower throttle openings. This is safe if you have to shut the throttle at high revs/throttle, and racers aren't bothered about being rich at lower throttle as they mostly run about flat out. The AS atomiser is more suited to road use start with an X13 needle, and if this is too rich even on the end clip try an X7. Always dyno or plug chop to ensure all is well.