Question about vintage dual sidedraft carberettors:

[Eubiewan Rastaberry]

Is anyone an expert on the side draft SU and Stromberg, jet and
needles?

Are jets essentially the same; only the needles (as marked) different?
Do these carburetors, fitted with various needle applications,
essentially each have common jets?

If, as long as needles match, is the only difference in jets going to
be any wearing, out? (Say, one carbo with a brand new jet, the other,
with used jet of unknown age, but both rebuilt with new needles?

Or, it now looks like I might have got two, NOS (SU) rebuild kits, but
of difference in production (i.e. fittings screw together, but each
kit is of different manufacture) so, aside from my dual carbs looking
odd, with different jets, mounted, is my only worry getting needles to
match? I know, how I might actually notice, wearing, in the needles;
but do the jets even wear, out (much, besides, just their leaking?)

Thanks

 

[User]

Is anyone an expert on the side draft SU and Stromberg, jet and
needles?

Are jets essentially the same; only the needles (as marked) different?
Do these carburetors, fitted with various needle applications,
essentially each have common jets?
Yes


If, as long as needles match, is the only difference in jets going to
be any wearing, out? (Say, one carbo with a brand new jet, the other,
with used jet of unknown age, but both rebuilt with new needles?
Yes

Or, it now looks like I might have got two, NOS (SU) rebuild kits, but
of difference in production (i.e. fittings screw together, but each
kit is of different manufacture) so, aside from my dual carbs looking
odd, with different jets, mounted, is my only worry getting needles to
match? I know, how I might actually notice, wearing, in the needles;
but do the jets even wear, out (much, besides, just their leaking?)

Thanks

In general the jets wear a bit more than the needles going to oval
overall as opposed to the needles that generally wear a flat spot toward
the motor side (spring loaded side) of the carb and just in the middle
of the needle travel. The biggest problem is air leakage around the
throttle shafts and throttle shaft bushings. Strombergs have the added
problem of diapragm failure.

Bob

 

[Pat Quadlander]

Both sides (dual carb) should be identical, with identical needles. One
side squirts cylinders 1 and 2, the other squirts cylinders 3 and 4.
Overhaul both sides at the same time (i.e, buy a complete overhaul kit.
don't overhaul just one, but not the other). And, have both sides part of
one complete system, not various parts from various systems from various
applications over the years.