my crystal ball remains cloudy but I do see SU carb work needed in the future.  Whatever PC I was using in the early 2000s has long since gone to recycling, nothing on this laptop in my saved files on SUs, found a print from the SU Search program in the file cabinet. Forum search brought me here to this thread from 7 years ago.  Thank you MM hosts for keeping years of the forum searchable.
Hope something I post below is useful 7 years from now as well.

Was not surprised that SU Search spreadsheet link is long gone from the web, but I was still able to download a working copy from 2009 using the Wayback Machine https://web.archive.org/web/20090213153557///homepage.mac.com/crscapps/CSA/Page3/Page3.html

Mintylamb is still up //www.mintylamb.co.uk/suneedle/

MK1 conversions has needle software at https://mk1-performance-conversions.co.uk/technical_carb.htm

Other sites suggest WinSU software (not free) at https://www.winsu.co.uk/

I havent tried that one yet.

Not jets/needles, but DrMini mentioned flow issues with K&N filters in 2016.  Vizard's TtASE book showed improvement but that was with stub stacks.  What the heck, Googled and found STL files for 3D printing stub stacks here: https://www.printables.com/model/596287-su-hs2-carburetor-velocity-stack

In my recent experience, K&Ns (both types) for SUs have too much restriction. We recently built an 1108 (998 with 68mm bore), Russell RE266SS cam and found that the twin pancake K&Ns on the HS2s restricted it above 5000 rpm. Needles are AH2. So we replaced the K&Ns with Lynx Ramflo filter and Unifilter foam. It screams to 7000 now, no problem.

 

A friend had twin conical K&Ns on his fresh 1330 with the same RE266SS cam and 1.5 rockers. Twin HS4s, CP4 needles. Same problem, so he fitted Ramflos and got the same good results.

Glad to hear - 

Regarding the pre-ignition issue - lots of things you could try, depending upon which spark plugs or fuel you're using.  The standard distributor should be a good starting point for your engine - unless someone modified either the engine or dizzy...

First, though, I'd try retarding the ignition timing 1 or 2 degrees from wherever you've got it set at 3500 rpm (hold the engine at 3500 rpm (ish) and turn the distributor body anti-clockwise 1 or 2 degrees - assuming a dial-back timing light.

Otherwise, check the gap on your plugs, check your contact breaker points gap (affects ignition timing), check your valve adjustment, change to non-projected nose plugs (B6ES, for example, instead of BP6ES or whatever brand/heat range you use), increase your octane level, etc...

Hello
This is a pretty late update but maybe late is better than nothing.
I installed new AH2 Needles and new Red springs per the manual for Austin Cooper S.  I balanced the carbs set the idle etc. 

The motor is just a hoot!  It starts and runs just great!  We were at British Car Field Days in Sussex WI.  this past Fathers Day.  The car goes 65 MPH with out issue, (with out issue with the engine.  I will post a new topic after this one to explain a new issue.)

I think there is a little pre ignition or detonation to be heard when accelerating from maybe 25 MPH to 45 MPH in second gear.  The distributor is original with out vacuum advance or retard.  I have completely dismantled, cleaned and reassembled the distributor about a year ago.  Not sure what I can do to eliminate the pinging.  Any suggestions are most welcome.
Regards
Tim

One mistake that I made when rebuilding my HS2 twins was when reinstalling the jet to float chamber tubes(I may not have the right names). I was careful, but the neoprene gasket slipped and partially blocked the feed.This showed up more on acceleration , but it could probably present itself in different ways, so even simple things can cause issues.

Twin HS2's suffer from throttle shaft wear and if so idle horrible and create all kinds of running issues. Make sure you have zero play by taking off the return springs and checking for movement, also with it running you can use a 2 foot piece of hose near the shafts where they run in the carb body and listen for a hissing sound. If so you have an air leak and no amount of tuning will overcome this.

Hello.
Good questions.  Definitely something to look at. 
I don't mean to lay out the life story so sorry if TMI.  I bought the car in pieces.  It wasn't driven in over 30 years.  I did a complete rebuild meaning all the systems cleaned, flushed, new items etc.  So I really don't know how it ran or didn't run from when it was put in storage.

Last year I actually had to remove the head.  The bypass hose  was rotten thru out.  I could not get the cylinder head bypass hose adapter removed.  The threaded part was the only portion left of the adapter.  So I took the head off, had it looked over, valves checked etc, installed new hose adapter and reassembled.  I cleaned all, new gaskets etc, I adjusted the valves, set all to specs but it still ran like before which is not good, (I believe rich and missing, hard starting, plugs wet.) 

I think I need a place to start.  I am going to install new AH2 needles and new red springs per the manual.  I will check and double check valve clearances, timing, vacuum leaks and what not.  Then install the new needles and see how she goes.  I am thinking if it is a standard "S" motor these items should allow it to run quite well; I hope.
Thanks much. 

It's all making me consider getting a Colortune and no more relying on my research and finger crossing.

Tim: Have you re-checked the basics? Like an air leak? Or loose manifold or carb nuts? Oil in the dashpot dampers?
The mystifying issue is that you have removed, cleaned, tidied up and reassembled what was apparently there to begin with. Presumably it ran that way once and would again.

If 007's are anything like 006's they would be way too rich for a standard S engine. There are some seat-of-the-pants tuning steps. Have you tried the piston lifting pins yet? The process should be in your Haynes manual. A fuel smelling exhaust is a sure sign the mixture is too rich. Also the appearance of the plugs gives you an idea of mixture.

To Jeg: WOW! Thank you! Love the info and words of wisdom. My mini is an "S" with factory installed HS2 carbs.

The springs could be light blue. They appear to be grey, uncoated steel. Maybe they are not original to carbs.

I am going to purchase red spring AUC4387 and new AH2 needles from MM.

The manual calls the needles Needle jets. The existing needles installed in the carb is in fact factory stamped with 007, meaning it is not for example hand engraved. I am also taking an educated guess that it is zero zero 7 not oh oh 7 as the zeros are, well zeros.

To Tmsmith: Yes I went thru the process, by the book. I have a very nice carburetor synchrometer air flow meter which I highly recommend, verses the usual choke down bead bouncer type. I had all items set, I think, but could not get it to run correctly. This prompted me to start over and check just what I actually had for componets compared to the manual. As for wear; I had the carbs off, cleaned and checked all items and all looked to be good including the floats and other items.

Thanks again all. Very much appreciated.

The H4s on the Radford have wonky numbered needles in them (may even be the 007s mentioned) which were installed by a leading US SU carb expert who badly rebuilt them.  

IIRC they are an aftermarket copy of an SU profile, very possibly an AN based on some quick Googling.

If this is a twin setup, then have you gone through the basic setup and synchronizing process?
If these are original carburetors, then there can be wear that will affect setup and running.

The MK1 Performance Conversions website has a much better needle comparison resource than Mintylamb.  This LibreOffice-based needle profile resource compares the annular area of selected needles, including needles from different 'families' (0.090", 0.100", 0.125") as well as allowing the user to compare 'fixed' to 'biased' type needles, as well as a modified needle to a 'factory' needle.  The Mintylamb program is rather 'one-dimensional' in this respect.  Another benefit is that you can simulate the effect of raising or lowering the jet, and have access to all of the needle profile dimensions, and can download it to have it on-hand at any time.

needles.zip 

I digress...

There are no 'grey' SU carb springs, you probably have light blue 2½ oz (AUC4587) and are possibly interested in installing a pair of 4½ oz red (AUC4387) with your new AH2 needles.

Be aware, though, your original post stated '007' needles.  There's no such thing as '007', but there is an 'O7' needle which is very different to the more common '7'.  So, accuracy counts...

In these images, I've selected a working range of '11' measured points along the needle profile, as I don't know if you've got twin HS2's or twin HS4's.  If HS2's, then use only the first 9 points.

There's lots of good reading on the Berlen Fuel Systems website tech section...

A rolling road is a chassis dynamometer.

Those are needles you are quoting not jets. You will need an air fuel ratio meter at least and even then it is a stab in the dark with a pair of needles costing $30 plus it can get expensive really quick but not as expensive as running an engine too lean with the wrong needles and blowing it. I would go though all the needles on the chart and start off with the richest one and go from there, it is a lot easier to do with an a/f meter though.
As with any car you need to make sure everything else is tuned up correctly, ignition timing, points and condenser, cap, rotor, spark plugs, spark plug wires, valve lash etc before you touch the carbs.

Hello and thank you for the reply. The website is pretty cool, thank you. Might be too much info for my little brain but I will give it a shot. I think my NJet 007 which is stamped on the straight, shank needle mounting area is listed on the website as just "7". I have other NJets which I don't remember how I got them, D3, RF, RG, SL, V3 which are all listed on the website. Kind of looks like the PO did some tweeking with the motor. And back to the question; What is my next step? Sounds like this may be a long trial and error method, which I think is what you mean with "rolling road session" but I would sure like to hear anyones stab at an approach to this opportunity. Thanks much. Tim

You can compare the needles at mintylamb.co.uk. I am not sure but the AH2 may be a swinging needle wheras the M is fixed but you can remove the collar if you decide to use the AH2. Not knowing what the build spec is or isn't is going to make fine tuning difficult and you should look into a rolling road session. Not sure what you mean by 007 N jet, all the jets on HS2's are 90 thou ones maybe you mean an N needle. 

Hello.
I have a 1965 Austin Cooper 1275 S that I bought in pieces a few years back.  It is finished, almost.  It was running but would not idle, stated hard warm and or cold so I thought I would check out and set or play with the carbs.  (I do not know what has been done to the motor if any modifications.)  I removed the carb piston and needle jet and found,
Needle Jets - 007 
Spring - Grey
The shop manual states factory specs:
Needle Jet - M
Spring - Red
I also read with my KN filters, to go one richer:
Rich Needle Jet - AH2
Lean Needle Jet - EB (for FYI)

So the question is; What is my next step?  Buy the richer AH2 needle jets and factory Red spring?  How does the NJet 007 compare to NJet AH2, if that is a question to ask?  Curious why the PO installed 007 NJets.  I have searched online and find some info relative to NJets but it is obviously more involved than what I see on the surface.
Thank you for any help.
Regards
Tim