----- Original Message -----
From: "David Tinker" <david.tinker@virgin.net>
To: "Lani Spahr" <lani_spahr@agilent.com>; <mg-tabc@egroups.com>;
<mg-t@autox.team.net>
Sent: Monday, July 17, 2000 11:26 PM
Subject: Re: SU balacing
> Hi Lani, If I was in your position my first job would be to remove the
carbs
> from the head ( I know its a chore ) and check if the throttle plates are
> closing. The best way to do this is to look through the ports from the
> manifold side. You should see no light showing or very little, and the
> important point is that both throttle plates should be about the same. If
> the plates are not seating perfectly then slacken the two screws that
secure
> the plate to the spindle so that the throttle plate is loose and apply
> pressure to the throttle spindle and the plate should seat perfectly.
> Tighten the two screws while keeping the pressure on the spindle. Make
sure
> that both throttle plates are showing similar levels of fit.
>
> The uncentred jet must also be rectified and several checks should be
made.
> 1 Check that there are no dents on the dash pot flange so that it seats
> squarely on the carb body, any imperfections will cause the dash pot to
> "kick over" when the screws are tightened.
>
> 2 Make sure the needle is not bent, and that it is inserted in the piston
to
> the correct depth.
>
> 3Check that the piston moves freely in the dash pot bore.
>
> These are the main problem areas, and if these solutions do not work then
> check the condition of the throttle spindles and bearings, the bottom jet
> bearing , and associated parts.
>
> My bet is on the throttle plate not seating correctly!!.
>
> Keep us informed,
>
> David Tinker
> ----- Original Message -----
> From: "Lani Spahr" <lani_spahr@agilent.com>
> To: <mg-tabc@egroups.com>; <mg-t@autox.team.net>
> Sent: Monday, July 17, 2000 3:18 PM
> Subject: SU balacing
>
>
> > Hi all -
> >
> > Yesterday I embarqued on the final stage of my first thorough tune up of
> my
> > TD (I bought it last summer) which is carburetter (!) tune up and
> balancing.
> > I followed the procedure as outlined in Knudson's T Series Handbook.
When
> I
> > came to centering the jet on the front carb I had a bit of trouble
getting
> > it centered. The problem was that it was centered with the locking nut
> loose
> > but when I tightened it down the piston did not seem to go all the way
> down
> > and "click" on the jet. After several tries I got it to center (I
> think -see
> > below). Now for balancing the 2 carbs:
> >
> > I adjusted the 2 throttle screws as described (until they just touch the
> > plate and then one full turn CW), started the engine (which idled very
> well
> > at a slow speed) and listened with my tubing/stethoscope to the air
> intakes
> > at each carb. The front one (the one that I was having problems
centering)
> > was sucking MUCH more air than the rear, so to balance them I had to
> adjust
> > the rear one CW several full turns. Even backing off the front screw (to
> the
> > point where it isn't touching the plate at all) to get a balance results
> in
> > a very fast (2500 rpm) idle speed. If I proceeded to adjust the mixture
> from
> > this point I doubt that I could get the revs down to an acceptable
speed.
> >
> > Now to the questions:
> >
> > 1. Do I still have an uncentered front jet, i.e. does an uncentered jet
> > result in a greater air intake that I observe?
> >
> > 2. If not #1 above, do I have something wrong with the throttle plate?
Is
> it
> > adjustable somehow other than with the external adjusting screws? As
noted
> > above, when both screws are adjusted the same the front carb is REALLY
> > sucking air.
> >
> > 3. Anything else?
> >
> >
> > Cheers,
> > Lani Spahr - 1951 TD #5550
> >
> > Bruckner Symphony Versions Discography
> > http://people.ne.mediaone.net/lspahr
> >
> >
> >
>
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