Scott -
Don't despair!
There actually are a number of ways to dial in your Webers. Keep that in
mind. The combinations of items to get there are pretty diverse, so you
need to understand the relationship between the components. Things that
effect the carbs: cam - timing - state of the ingnition - the amount of
backpressure on your exhaust (you have a header, right??)... driving style.
Lots of factors.
I found that I had to replace the idle jets on mine. I also changed just
about everything else, but the idle jets provided the biggest quantum
change in getting my car to run okay. Keep in mind that much of your around
town cruising is on the idle jets - really. Especially if you drive within
the posted speed limits in many states, and I'm not talking about Montana
here.
The books all say - Make sure your ignition is up to the task. This is
sagely advice. If your ignition sucks, your car will run like $#!^. I
heartily suggest electronic ignition, I happen to have the Crane system.
Others will work well too.
A couple of things...
1. Get a book. Get two books. Read them, if just for the exposure. I
suggest Passini (tough to comprehend, but all the good stuff is in there),
and Webers by Pat Braden (HP books). There's also one from Haynes...
2. I don't have the numbers handy, but several folks on this list were very
helpful in helping me get my DCOE 40's set up. There was a spreadsheet on
this list a while back... Oh, I just found one posting from Leon Guyot (Hi
Leon). I'll post it to the list if anyone cares, but the bottom line is
that the Idle Jet should probably by F9 and you should probably use the
0.45 orifice with that F9...
3. I wound up switching to 28mm venturis because the Solo II A Prepared
specs for TR6 indicate that you must run 28mm - this was pricey at $120
($180 from the big three if you don't shop around!) and should only be done
if that's where you are headed with your Webers.
4. A dyno is really important to help you figure out if you are making
progress when you change stuff, but the time on the Dyno is around
$100/hr., so you need to show up with a box - o - jets if you intend to
actually tune the car. This is where it is helpful to find someone in your
area that knows Webers and has dyno access. Note: you can do this with a G
analyst and an open stretch of road - the G analyst is around $135 -
speeding tickets are extra!
5. The numbers of the emulsion tubes are not linear - this is where the
books come in handy. For example an F8 might not be "richer" than an F9
(although F8 and F9 in this example are purely hypothetical - I don't have
any Weber books near me as I write this.
Here's what I think I have in my car:
Choke<28mm>Main Jets<1.15>Emulsion Tubes<F11>A.C.Jets<1.55>
Idle Jets<0.45/F9>A.Pump Jets<0.45>Auxilliary Venturi<4.5>
I know that the carbs had F8 idle jets when I got them and I replaced those
with F9's. I also changed the accelerator pump to 0.45 from 0.40, but I
don't think that was actually necessary.
6. learn how to "read" your spark plugs - all the data is right there for
you to see. You just need to know how to read them. Also, learn what a
"plug cut" is. This is the only way to read the plugs from wide-open-throttle.
All in all, I spent probably about $200 on extra jets and the 28mm venturis
to get my car working okay. It's still not perfect, and I'm saving up money
and buying jets and air correctors so that one day I can spend an hour or
two on a dyno.
That's all for now,
rml
p.s. if you live in the Boston area, I could probably help you get your car
dialed in... it's really not that hard.
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