If they don’t make one, please, who does?? I need a B whistle…
I haven’t seen a B generation only Bb. Doesn’t mean they don’t make one, but I have never seen one.
Susato makes whistles in every key if you are looking for an option for under $100. Might check them out.
Search for previous threads. Instruction how to trim a Bflat one into a B have been posted here several times. Easy and quick job.
I haven’t tried this, but I suspect that by merely trimming the whistle tube, you might end up with a whistle where all the notes weren’t in tune with each other.
Don’t knock it until you try it.
You take off a bit at both ends, works a treat. I have seen Ronan Browne perform the operation half an hour before a gig. Not a bother.

Right! It’s a pretty regular/common hack, IME.
Look at this thread where I referred to previous threads with the DIY instructions.
https://forums.chiffandfipple.com/t/anyone-have-a-lead-on-a-b-whistle/80910/1
The result of that thread was that an F# whistle was actually needed. So I made one (from scratch, no gens involved) and played in F#.
Also in that thread someone asked about turning a Gen Eb whistle into an E whsitle so I dug up the measurements for that one and posted them there as well.
Making a C# out of a Gen C is also done in a similar manner. Cobbling up an A whistle from a Gen Bb involves a little more effort.
Feadoggie
There is also this very recent thread on making a B whistle using a C head:
I was hoping that Pancelticpiper would post these instructions he sent me:
I just got out the B and took some measurements.
Since I’m not sure how much I cut off (yes I do have another Gen Bb but often Gens are a bit different from each other) I’ll give you the lengths of top and bottom measured from the top fingerhole, the hole from which C# emits on a D whistle.
So:
from the centre of the top fingerhole to the top end of the whistle (where the head would go) 5 inches or 12.7 cm.from the centre of the top fingerhole to the bottom end of the whistle 6 7/8 inches or 17.5 cm.
The sizes of the two bottom fingerholes (from which on a D whistle the notes E and F# would emit) : oval, height of holes 1 cm or 13/32 inches. These holes were carved on the side of the hole nearest to the top end of the whistle (the head end) only; in other words, the edges of the holes nearest to the whistle’s bottom end were left as is. Truthfully speaking these two lowest holes aren’t ideal; the ideal would be normal-sized holes a bit further up the tube so that the fingerhole size/position pattern would be the same as any other whistle. But my whistles like this (B and C#) both play great, right in tune, so I’m not complaining.
Jerry Freeman recently posted that he now offers a tweaked Generation B whistle at your request. He creates them from Bb whistles as well.