Have forward movement in all gears...... including reverse.

Started by Funpig, January 10, 2017, 06:49:43 PM

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MPlayle

ABY would be even more rich than what you already have.

Have you tried the first site I linked for comparing the needle profiles?  Select the range for the HS4 carb and plug in the AAG as your current needle.  Then select other possible ones in the "New Needles" boxes and see their graphs compared to the AAG.  You want a new needle whose graph falls below the AAG in order to be leaner.  Above your current needle is richer.

Your option of the ADE is a leaner needle, as would be the ABB needle.  The ABB is a bit more linear in profile than the ADE.


Funpig

MP...  Yeah thank you for the link.  I have been putting in for a number of different needle types and it looks to me (total noob with carbs) that the AAA and AAB look to have leaning characteristics that may alleviate my problems based on the charts they show.   With this said though it seems that it is still just a shot in the dark as I don't know how much richer from normal I am running from what it should be.   Unless there are any other suggestions I think I am going to put in for one of the mentioned needles tomorrow and maybe by the end of the week have it working a little more normally.
Thanks for all the input!

MikeB

John Gervais

Not that I expect to be heard, but the AAG is a standard needle for 1972-1973 Canadian minis.

The red 4oz spring is normally used in near-stock stage 1 setups, so you'll probably be good there.  Your damper should be AUC8103.

What grade of oil are you using in the carb?  Genuine SU oil (is about 20W) or engine oil?  The thicker the oil, the greater the accelerator pump-like enrichment effect (carb piston rise momentarily slowed, increased depression (more suction) over the jet).

The AAU needle is most commonly used in stage 1 kits, the AAA is used in the performance stage 1 kits (HIF38 +/or large bore exhausts)  and is extremely versitile.  Thereafter, AAM and AAB would be astronomically rich at top end -

ADD is a weaker needle, and was used in 1975 Canadian 998 minis.

I've done some needle comparisons, if you'd like to see them (AAG vs. AAU, AAA, AAM, ADD, AAF, ABD, ABY) I can post them - I've got all the needle data in Excel files, and have WinSU and the newest not-yet-available Needles program.  By comaring annular area, you can see the percentage difference between small adjustments of the jet or between 2 needles.  It's much more accurate than looking at dimensions and ignoring the SU % change curve charts - as you can see in the AAG vs. AAU and AAG vs. AAU with 0.006" raised jet - the percentage difference is noticeably leaner at positions 4, 5, 6 and still give significant richer fueling above position 8 (keeping in mind that the 1½" carbs only open to expose 11 or 12 needle positions).
- Pave the Bay -