I decided to run my '85 1.9l with the O2 sensor unhooked from the FI system
and wired to my digital voltmeter.  The readings were high, consistently
ranging from 0.8 to 0.85 VDC.  I then reconnected the O2 sensor and then
"teed" in the voltmeter.    The ECU adjusted the mixture some, dropping the
voltage to 0.7 to 0.75 VDC.  Is this still too high?  Is it worth opening
up the AFC and tinkering with the spring?
A couple of interesting observations.  The O2 sensor puts out a usable
voltage in less than a minute---this is the one-wire type.  I thought it
would take several minutes to heat up.  When you get off the gas, the O2
sensor voltage drops to almost nothing, and then recovers after a steady
exhaust flow is established.  It takes awhile at idle to level out.  The
WOT switch does work!  It goes to 0.9VDC when you floor it--with or without
the O2 sensor connected.
My conclusion is that if your engine runs better with the O2 sensor
disconnected, you have other problems. You probably have a  vacuum leak and
the richer open loop mixture helps correct it.
How many notches should I move the AFC spring (and which way) to lean it
out?  This a new AFC, by the way.
As a side note, I am running my timing at  "0" TDC and it does seem to run
better.  I am hesitant to advance it much farther.  Would this affect the
O2 sensor readings?
                                                   Jay '85 Westy