Hitachi SU with A 7 Needle

[roadsterred]

My 1968 2000 is a work in progress. It has been through several owners (my guess) and it's equipped with a B cam and headers. I removed the carburetor pistons to identify the needles and they are marked A 7.

Did a search on the Internet and this forum but wasn't able to find any information on the needles.

The engine is running rich. I can close the idle mixture screws and the engine will still respond normally when I blip the throttle. Checked to see that the needles were installed properly, they were, and am running out of ideas.

[ACote]

http://www.311s.org/pmwiki-311/pmwiki.p ... sNewSuTech
Has a lot of good info on needle performance, unfortunately I didn't see A7 either. When is your car rich? Idle?
If at idle you could try and install the needle slightly protruding .01. The Needle pistons usually are matched to the housing as well, just test them out and see if one moves more or less then swap and see if they're more even.
like here:

[ACote]

There is a few common problems in that tech wiki that could help with the richness issue.

[nismou20]

I’ve fiddled with many a needles but have never heard of those either. If mostly stock other than a B cam I would get a pair of RA needles and chuck those. Also over time the nozzles may elongate wear if the needles are not centered rightly causing richness. Dean carries them.

[roadsterred]

Thank you all for your suggestions. Will let you know how it turns out the next time I work on the car.

[greydog]

Our 1600 was similar. At idle, the car was slobbering, eye watering rich. I finally decided to start from zero and set the jets to the "magic number". In doing so, I realized that the choke cables were holding the jets in enriched position at idle and the two jets were different heights (neither correct).
A bit of adjustment and she idles great, no longer cold starts without a choke and doesn't make you cough before you can back the car out of the garage.
Point is, I'd bet on base jet adjustment being the issue.
Dan

[Linda]

Can the ADQ needles be used in a 2000? They do work nicely for the 1600.
Linda

[RustBucket]

I wasn't able to find A7 on a search. You could measure the stations on the needle and compare them to the needles on the attached chart to see where it fits best. Maybe you can find one that will give the curve you want. Good luck.
Rustbucket

SU_Needles_27.xlsx

[Linda]

712 possible SU needles? Wow
Linda

[keith0alan]

The ADQ needle does not work in the 2000s. I have other needles for them.

[roadsterred]

Re-adjusted the needles and idle mixtures on both carbs. The idle is still rough at around 1,000 rpm. As for driveability, smooth acceleration and cruising. Will let it go for now.

Thanks again to all of you for the information and suggestions.

[Gregs672000]

Be sure to check carb balance again as well... just a little off and you won't get a steady idle, especially if the throttle shafts or other parts are worn. You will also have a harder time getting a nice idle with the B cam due to overlap... your carbs etc would have to be really dialed in to be perfect, hard to do with an SU type carb where as a Mikuni or similar is more finely adjustable and has separate systems to adjust.