Buying Other People’s ProblemsIf you buy a side draft carburettor off ebay or gum tree or enthusiasts website in 9 cases out of 10 the carby will have a problem that will prevent it from running out of the box. In my case that statistic is 17 out of 17 as I have never managed to get one fit to use from the get go.
People sell side drafts out of frustration or because something is broken or missing. In advertising speak, “Was running on car “ translate to "running so rough I could not stand it” and “professionally tuned” translate to “I have a mate with set of jet drills”. Ebay is a place where lemons are passed from hand to hand and each hand inflicts some further molestation.
Not all bad news as long as you bid with the knowledge that further expense will be likely and know how to diagnose and fix the problems that have frustrated previous owners. And that is what this new section is about – profiting from previous owners lack of knowledge and skill.
Some Horror Stories
Here are some rippers from my personal list:
Wrong butterfly plate fitted – first progression hole permanently exposed,
Floats – busted, twisted, broken mounts you name it
Jet drilling day at the local kindergarten – needs no further explanation.
Corrosion – jammed idle screws (tower type), aux venturis, chokes
Broken aux venturis
Surprise! No jets fitted under the cover.
Surprise! Not check ball in pump jet circuit (not fitted in the factory)
Butterflies (aka spindle shaft and throttle plates)
This simplest part of a side draft can often cause the most frustration.
First check is that the throttle plates completely cover the first progression hole with the idle stop fully wound out to recommended setting (half turn to a turn). Some throttle plates have sweeps / flutes cut in them and some don’t depending on the location the first progression hole is drilled. If the butterflys have been previously molested the wrong plates can be fitted as in the photo below.

Dellorto 45 throttle plates came in 3 variants but now only the .1 type is available and it has progression hole sweeps. For an application that requires no sweeps you flip the throttle plate 180 degrees – not just backwards but backwards and upside down so that the bevelled edge of the plate rests evenly on the throat. Photo below is the same carb with flipped plate. First progression hole now exposes just off idle
[URL=http://s434.photobucket.com/user/tobytj_bucket/media/Side%20Draft%20Carburettors/6d93fcff-7afe-41e9-b413-91af92c31696_zpsjfwhj6vs.jpg.html]

[/URL