Triumphisti,
The Zenith-Stromberg CD-SE and CD-2SE series carbs
are indeed matched at the factory as an air valve, cover, and carb
body set. Take a look at the top of the carb body, just above the
throttle butterfly. You'll see a lead plug that covers the "leak
balancing screw". To quote from the Haynes Stromberg carb
manual, page 39:
"To compensate for the very small variations in
component sizes (air valve diameter and body bore diameter)
due to manufacturing tolerances, an adjustable screw is
incorporated to provide an additional air bleed between these
two regions....Once the screw is set, on initial build, it must not
be altered...The body, air valve, and cover become a matched
set and neither (sic) part must be replaced independently
of the other..."
Having said that, I'm running a replacement
air valve and cover in one carb on my TR250 with "good
'nuff" results. Our carbs are worn enough by now that the
advice might be academic, especially if you've had
Apple Hydraulics bead blast the soft aluminum (as I
have). But I would not advocate taking emery cloth to
these parts on the assumption that the presence of a
rubber diaphragm makes tolerance issues moot.
Best regards,
Tom Marincic
CD3574L
carbs balanced at idle only...
Dave Terrick wrote:
FYI, AFAIK the matched set theory is only applicable to SU carbs, as they
use no diapraghm for sealing top to bottom. Thus, a machine tolerance
finish is required!!
|