> When it comes to carb needles, though, I'm in the dark. I
> checked the two SM
> needles in SU H6 carbs on my TR3A, and both showed a slight
> degree of bending
> as I rolled them on glass. The tips on both wobbled ever so
> slightly to the
> same degree as I rolled the shank. My question is, do I need new
> needles and
> jets, or is being out of concentricity to a small degree
> acceptable? At what
> point does it become a real performance issue?
>
> Thanks for any tips as I'm relatively new to the fixed needle S.U.s.
Bill, the main issue for the fixed needle carbs is that the needle cannot
contact the side of the hole in the jet. If it does, it will both prevent
the piston from seeking it's proper level, and cause the jet and needle to
wear at the contact point. (This wear inside the jet can be a difficult to
find source of overheating problems.)
I don't know how to tell if your needles are bent "too much", I suppose one
way would be to smear some machinist's blue on the needles, install them,
remove them, and look to see if the blue is rubbed off at any point,
especially near the thickest part. IMO, it's better to just replace any
suspect needles, and the jets they were running in.
Randall
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