Anyone know the recommended carb size and jet specs for a Concentric on a ZB32?
Thanks.
Take a look here
https://partsbooks.britishonly.com/
You might find some info.
I don't think that there will be a single 100% correct answer to your question as it will depend a bit on the exact spec of your engine (tourer, scrambler or clubmans or trials). Do you have a silencer, twitter pipe or straight through? Velocity stack or filter? Std (7.5:1 or HC 9:1 pistons)? Touring or hot cams?
Basic would be a 1 1/16 or 1 3/32 choke size RN or 10TT replacement so either 626R (627 were used on Tridents) or 928R for starters (right side tickler) smaller would be better for general tootling around.
Typical slide would be a 3 or 3.5.
Needle would be two grooves above clip ring.
Typical needle jet would be a 106
Main jet would be by experimentation but 220 would be a place to start and adjusted after a couple of plug chops.
What have you got?
Thanks for the reply. I don't "know" what I have as after 70 years of fiddling it could have many cams, pistons, etc, and until it's stripped at some point there's no way of knowing. The pipe is probably identical to the contemporary B31/33 as the plunger frame isn't conducive to fitting the more usual Goldie silencer.
The intended use is little more than general road use and not stressing the old girl, as parts are too expensive/rare to contemplate a blow-up repair.
Currently it has a 10TT9 carb fitted which I'd like to remove and set aside while a more suitable Conc is in use. I'm guessing a pretty-much standard B31 carb would be more than adequate for my purposes.
Thanks Andy Kay, that's a useful link you provided.