Wait wait wait. I am NO expert on SU carbs (or much else for that matter), but
I find it very hard to believe that each piston and dome were percision honed
and matched as a set at the factory. It has been a while since I looked
closely at an SU carb (I have SK sidedrafts) but as I recall they appear to be
cast aluminum parts to me. I can imagine that there were specific tolerances
and some final machining or clean up, but are you telling me that there was
some guy at the factory that specifically matched each dome with each piston to
the degree being suggested? And he would do this by...? He would check his
work by...? To be sure of his work, I think it would have to be set up on some
kind of airflow bench. Sounds VERY labor intensive to me. Unless you
radically sanded the thing, I cannot imagine that the tolerances changed much.
Again, please feel free to enlighten me. But for now, I suspect that something
else is contributing to the differences you see in the carbs.
Ignorantly yours,
Greg Burrows
-- Keith0alan@aol.com wrote:
Hello all,
Puttering with SU carbs today and found an excellent example of what
not to do. When cleaning the inside of the dome and piston DO NOT USE
SANDPAPER. They are precision honed and matched as a dome piston pair, so, also
make
sure that you don't mix them up. Carb cleaner and a rag or paper towel work
fine
for cleaning. Carquest brand of carb cleaner seems to work the best.
The result of the sandpapered dome and piston? With the same air flow
it only raises about half as high as a good one.
keith williams
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