Hi Cliff:
As for rebuilding SU carbs, I've gotten to the point at which I'll just buy
the components of the kit seperately as I need them. The O-rings on the
jets can be replaced at a hardware store for an extremely cheap price, if
you have a good one, bring it in so that you can match sizes with their
inventory. The piston needles don't wear out very quickly, especially if
you don't have a backfiring problem. Same thing with the float needles and
seats, though the gasket on top of the float bowl seems to decay after a few
years. As long as you routinely change the fuel filter, it is unlikely that
you will need to do anything inside the float bowl. There is another O-ring
on the piston damper that you chould occaisionally check, but again, this is
a cheap replacement at a hardware store.
Other things that you may want to check (and aren't part of the rebuild
kits) are the condition of the throttle and choke return springs, and (if
you have a late model carb) the poppet valve in the throttle plate. This
spring loaded valve can fail after a couple of decades, and lead to
backfiring and difficulty in setting your mixture.
The major long-term wear issue with SUs is the tendency of the throttle
shafts to wear down the carb body, causing an air leak. If you detect a
vacuum leak there, the carbs need to be reamed out by a machine shop to
accept a larger throttle shaft.
I learned quite a bit about tune-ups from the Motorhead video "Tune Your
Sprite or Midget."
If your only problem is leaking gasoline from the area of the jets, probably
all you need are new o-rings or new jets.
Regards,
Charles
'74 Midget
'68 Sprite
Bloomfield, NJ
cdsorkin@ix.netcom.com
"How about we duck inside for a Hen?"
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