[Healeys] What am I doing wrong? Needle/jet alingment

[Mike Tobin]

I've done this any number of times before as part of tuning/cleaning -
loosen the lock nut , raise and drop the piston till it moves cleanly then
tighten the nut - and never had a problem.  Now as part of a rebuild i(new
jets) t's not working with two of the HS4s.  When I tighten the locking but
the  jet bearing moves and graps the needle.  I can't get the bearing to
hold still no matter how I fiddle with it.  Don't know why one worked per
usual but not the other two.
Cheers,
Mike Tobin
Pepperell, MA (above freezing all day (barely) for the fist time in days)