>Greg Burrows
> Greeting list! Well, I am getting closer (slowly) to trying out the 48
> mm SK carbs on the ol' U20. Since I am starting at near zero actual
> knowledge of jetting with this carb on my particular engine (other than
> what I can read in Weber tuning books, and who ran 48 mm Webers on a
> Roadster?), I am sure it will be a trial and error process to get it
> close, then dyno time to get it right. So, I am putting out a "request
> for Weber DCOE jets and emulsion tubes" that I might borrow for this
> process, guaranteed to be returned (or replaced should something
> happen). Jets run about $4.50 each, and emulsion tubes about $17.00,
> and with each change being multiplied times 4, one can see how a budget
> can be blown pretty fast if I don't start out fairly close. So, if any
> of you racer types out there have some Weber DCOE jets sitting around in
> a box saying "use me! use me! I want to be useful again!" then let me
> know and I will be forever in your debt. Thanks!!! As an update
> regarding the water/alcohol injection, I am getting closer, but decided
> that I need to get the carburation and maybe timing curve issues
> completely worked out before proceeding with that any further. I have
> taken some digital pics of the airbox as some requested, and with my
> wife's assistance I hope to have them available for those who were
> curious. I am aiming for Shasta, but unless I can get this beast fully
> sorted out, I may not risk it... we'll see!
Greg,
All of my parts and most of my books are still in storage, but I'll offer
the following couple or three points. Before I get started, what kind of
shape at these carbs in? If they leak air around the throttle shafts and
have other problems, you'll never get them running right. Also check out the
Weber pages on Jason Gray's site <http://home.att.net/~jason510/>. Click on
the "Weber" link.
First there's usually one or two emulsion tubes that work on a given engine
and if you don't have the correct E-Tubes you can swap jets and chokes (aka,
secondary venturis) forever and not get the jetting right. I'd contact
Pierce Manifolds and (is it?) Overseas (or International) Distributors and
see what they suggest as a starting point. Second, I'd tend to go small on
the chokes (or can you NOT change chokes on the SK? I seem to remember
something like that.) unless you're running real steep (4.38 or taller)
gearing and unless you plan on buzzing the motor all of the time.
Finally, adjust the jetting from the bottom up, because each circuit builds
on the "previous" one. Hope this makes sense.
HTH,
Ron
Ronnie Day
rday@hot.rr.com
Ronnie_day@acd.org
Temple, TX
***********************
'71 510 2-dr (Prepared Class Autocrosser)
'73 510 2-dr (Street Toy)
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