Kevin---Running down your list of questions--The jet orifice on the ZS
carbs is listed at .100--The widest part of the B1AF needles comes in
around .096 so a "loose" needle would indeed go all the way thru the jet
without stopping, if allowed to do so.
Since these needles are biased to one side by slight spring pressure,
there will be some striations from rubbing the jet. It takes a good eye
to see this, plus a lot of miles for this to show up. If enough wear is
present at the top (visible) part of these jets, it could permit rich
running even with new needles, but I've never seen jets worn this bad.
It's very unusual to not be able to lower the needle(s) far enough to
lean out the mix. To be sure that they are as low as they can go, take
the top off each carb and physically watch the needle drop as you turn
the adjustment screw. You'll probably separate the adj. screw from the
threads that control its height by doing this, but it can be re-engaged
by then pushing up on the needle while turning the screw clock-wise. At
least this way you'll know you went as lean as possible. (I'd be
surprised if the engine will idle on this meager diet.) *
If you feel or see that the needles are worn flat on one side, they can
be purchased at your favorite TR6 parts house. Ask for the B1AF
adjustable set.
*You didn't mention where you set the float heights. Obviously if too
high the fuel will flood the jets and perform as a rich, but raggety
mixture. The book says around .625, but you can go as "high" as .750
and still get a good idle, other things being equal. Also be sure the
fuel level (Grose?) jet is snug in each carb, so fuel won't trickle in
when the float says `stop.' (This is VERY important if you happen to
have an electric pump.)
Dick T.
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