[TR] SU H6 Carb Part Need

[Randall]

I don't have the link handy, but somewhere out there is a video, done by
John Twist IIRC, showing the "drop test".

Basically, you plug the holes in the bottom of the piston, push it to the
top of the dome, and then time how long it takes to fall out.  (Obviously
catching it as it does.)  There was a range of acceptable times (something
like 3 to 7 seconds, don't recall exactly); but the main point was that if
you have managed to mix them up between a pair of carbs, one will fall much
faster than the other.

Of course, too tight is rarely a problem unless the dome is damaged.  If
there is a tight spot, it can be identified with a little machinist's dye,
then rubbed out with very fine sandpaper.  The domes and pistons are very
soft, so go slowly and try the fit often.

I've never had to reduce the diameter of a piston; but it should be easy to
accomplish the same way.

-- Randall