[Roadsters] ZTherapy carbs & needles--was su backwards chokes

Tim tputland at charter.net
Wed Nov 3 11:22:10 MST 2010


Paul, 

Do you know what needles you are using (and where you got them) that you put in those ZTherapy carbs? I may be having a similar issue with my newish ZTherapy carbs...I can't seem to get the mixture right. It goes from too rich to lean with very very little knob adjustment. Others have suggested to me that the needles that ZTherapy use in their carbs are not exaclty/perfectly  correct for the Roadster. 

Any one else have or wonder at this issue with new ZTherapy carbs?

Tim
Dairyland Datsuns

---- Paul Bauman <plhbauman at earthlink.net> wrote: 

=============
I know that needle profile seems to have a lot to do with when you are
as much as where you are.

I've been told that cars running in high altitudes run better with a
different needle than stock due to changes in air density. This also
seems to be the case with changes in fuel composition or octane levels
over the years.

When I bought my roadster in the 70s, it ran super on stock needles,
even ingesting 89 octane regular. Then I got married and put the toys
away. About 20 years later I decided to rebuild the car and found that I
could not get a decent idle and/or smooth revving above 4000. After
changing to a non-stock needle profile, things went back to running nice
and smooth.

Then the front carb would not stop leaking gas, so I got a rebuilt set
from Z Therapy. Until I swapped the needles to the non-stock profile I
used in my old setup, I had similar idle/revving issues. She runs better
than super now. Go figure.

By the way, I live in California. What's a 'choke'?

Paul Bauman
Westminster, CA
67 1600


More information about the Datsun-roadsters mailing list