Hi Jack -
I recently went through the experience of re-building the Zenith
Strombergs - 175 CD, C1875 on my '63 TR4 with the rebuild kit from Moss
part no - 375-138 + throttle shafts a couple of months ago.
Assuming you have performed an Ignition tune (set points, timing, renewed
condenser, plugs etc) and have set the air balance between the carbs
correctly, (I won't go into details, others on the list can explain these
items better than I can) & the other normal check points, I have a couple
off the wall suggestions:
Idea 1
The moss kit referenced above comes with metering needles for the ZS #C3043&
C3069. The needle number is 2H on the needles. For my C1875 I had to
purchase the 2A needles Moss part no 374-210. (The C number can be found
stamped on the front of the main body of the carb behind the air filters,
just look around them with a flash light to see the numbers). I don't
really know what would happen if I had put the wrong metering needles in.
Idea 2
After rebuilding the carbs I found that I had tightened the outer jet
assembly or Jet Holder (the big 'screw' that holds the jet adjusting screw
and the upper jet assembly) too far into the housing, causing the spring
that adjusts the mixture to bind in a lean setting, regardless of the
adjustments I made with the mixture adjusting jet. Just loosen the "big
screw" a 1/2 turn or so and check to see if the spring compresses /
decompresses appropriately when turning the jet adjustment screw.
Idea 3 - the Haynes manual recommends for rigidly held needles (such as on
my C1875) centering the jet by "partially unscrewing the jet holder and
pushing the air valve assembly to the bottom of its travel" causing the jet
assembly to align itself relative to the needle.
I ended up buying the Haynes Weber Carb Manual (Great section on Zenith
Strombergs), a Carb Synchronizer to balance air flow and a colortune (shows
sparkplug spark color for accurate richness) to set the carbs up properly.
I also used the carb adjustment advice at www.vtr.org maintenance handbook-
http://www.vtr.org/maintain/carbs.html
If these suggestions don't pan out or you have different ZS carbs than I do,
I'm sure someone else on the list can find a solution.
Happy Driving!
Dylan
'63 TR 4
-----Original Message-----
From: owner-triumphs@autox.team.net
[mailto:owner-triumphs@autox.team.net]On Behalf Of jack williams
Sent: Thursday, November 29, 2001 10:17 PM
To: triumphs@autox.team.net
Subject: carb rebuild
Okay, so I have rebuilt my twin Zenith Strombergs with a kit from Moss. I
went through all the steps on the registry list for setting them up. I no
longer have any leaks by my throttle shafts etc., but I can't seem to get
them to run right. Above 3000 RPM's and everything is pretty good. Below and
it just sucks and is not even enjoyable to drive. It spits and sputters and
the only way to take of is to rev it up and slip the clutch (something I
don't want to do). I tried the troubleshooting things and by all indications
it is running way lean. If I lift the piston ever so slightly it wants to
die which, according to my reading, indicates a lean situation. However, the
needles are backed all the way out, and the plugs are a nice tan. So what
next oh wise ones?
Jack
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