i have the sizes
choke tube: 17
main: 57
compensating: 50
slow running: 60
capacity tube: 2
progression jet: 100

quoted from the period "book of the austin 7 and 8".

as regards adjusting carburettor jet sizes to gain some improvement, I cannot say. I suspect there is no real value in it that will be noticed. however, I could quote Nippy jet sizes if you wish, though they are for a different type of carb.

Location: Herefordshire

Thanks Dave,
Will see what other responses there will be. It appears that Willie MC Kenzie does the jets , will give him a call in the morning.I am trying to get all of my spares in full working condition and dumping the rubbish.

Location: Oakley ,Hants

Some suggest that modern petrol, at least here, is less viscous or somehow altered and so runs rich. Based on consumption on the same carb car (not Seven) over decades I suspect some basis in this.
My father used to meticulously check mpg on our RP with the stock carb. On 200 mile trips at 40 -45 mph on winding roads with two (by modern standards small) adults and two chldren he regularly recorded 50 mpg with the petrol of the times.
But economy is not now usually top priority with Sevens
There is always the risk old jets have been meddled with. The taper of a safety pin can be used as a comparison gauge. If inserted very gently no damage. Jets are calibrated by flow and I have noticed variation when tested with a needle.The jet bore will likely be intentionally tapered.
The exhaust system has an effect on carburation. Unobstructed silencer seems to richen mixture.
When experimenting with jets everything else must be perfect or results prove little.
The jets sizes are listed in many places so seldom receive mention on the Forum.
Stock jets are so common you could lap larger using a needle, but mark. The number is nominal size in mmx100
Bob Culver

Location: Auckland, NZ