Vance---The last time I looked into compatible needles for the ZS
carburetor, there were only a few that were biased and adjustable, such
as the stock, B1AF. The ZS carb manual "selection chart" shows an
asterisk for those claiming to be "adjustable". Burlen Fuel Systems
(and Moss Motors) say this is in error. They are non-adjustable, so
machining must be done to get them to fit these carburetors. This is
what prompts many who modify their engines to go with the SU carburetor,
as changing needles then is a simple matter working the set screw that
holds the needle in the air valve..
If you have found that Burlen now has "hundreds" of adjustable eedles to
fit the ZS, let me know, and I will put on my orthopedic shoes!
Dick
Sender: owner-6pack@autox.team.net From:
vance.navarrette@intel.com(Navarrette, Vance) Date: Tue, Apr 19, 2005,
8:28am To: sloseke@holly.colostate.edu (Shawn J. Loseke),
6pack@autox.team.net (6pack), RazorBobSr@aol.com Subject: Tuning ZS
carbs. Was Goodparts (triple-Carbs)...
Shawn:
There are hundreds of
Zenith needles available, the same number as are available for the SU
carbs. Moss only offers about 6-10, but for mild tuning they had what I
needed. I switched to the Jag XJ6 needles, B1ARs, which were richer
(what I happened to need). I haven't researched what Moss offers in the
leaner category. Look in their catalog for carburetor parts for other
cars (TR4/TR250/Jag/etc) to see all the needles they offer.
If you want to see
everything that is available, go to Burlen fuel and order their needle
catalog. There are MANY, MANY combinations in there, so you ought to be
able to find what you need. www.burlen.co.uk The needle catalog gives
you the station values, so you can see which needles are richer or
leaner, and whether it is at idle, cruise, or power. If you ord3er from
Burlen, delivery time is about 7 days and prices are competitive with
the likes of Moss. A US source for ZS needles and tuning is Joe Curto.
He stocks most of the needles, and can help you get the one you need.
www.joecurto.com
The notion that there
are more tuning options for SU carbs is largely a myth. Both SU and
Zenith Carbs are still manufactured in the UK by Burlen, and Burlen
fully supports both carbs with a complete range of parts not to mention
hundreds of needle options.
I don't know what other
modifications you have made to your motor, but up to about 140 HP the
stock twin ZS carbs will flow enough air (with the correct needle, of
course) to meet the needs of your motor. If you are going beyond 140 HP
or so, you will need more carb for the motor. So says David Vizard, my
hero.
Cheers,
Vance
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