Ahem. Here is a close-up of the switch mechanism.
http://goo.gl/p9Ad0
The piece sticking out at about the 11:00 position is where the turn signal
lever attaches, and it is shown in the "left turn" position. It's not
actually in the photo, but there should be a brass piece wrapped around
underneath it, so it is making contact with the center contact (the flat
copper plate visible just to the right of the lever) and the left contact
(the dark rounded surface peeking out from under the left side). You can
see the missing piece (and its spring) to the left in this shot
http://goo.gl/Vt79b
The center contact is connected to the flasher on the fire wall, while the
left contact connects to the left turn lamps. So the switch is passing
current to the lamps from the flasher. Also note the compressed spring,
between about 10:00 and 11:00. It is trying to return the lever to center.
At about the 5:00 position, you can see the spring loaded roller that is
keeping the lever from returning. Below it is a hinged pushrod that you can
see sticking out beyond the surface of the body. (The pushrod is actually
installed the wrong way, operator error. Please pretend that the slanted
part slants the other way. Someday, maybe, I'll take another photo and
replace that one.)
Not shown is the cancellation ring, which turns with the steering wheel
(while the switch body is held stationary by the stator tube). But
hopefully you can imagine the ramp built into the ring. If not, the ring is
near the upper right in this shot http://goo.gl/pki3G Hopefully if you zoom
in, you can see the ramp on the LH side as shown.
When the ramp goes by from left to right (ie when the steering wheel is
turning to the left), the pushrod bends at the hinge and does not dislodge
the roller. But when the ramp goes by the other way (wheel turning back to
the right), the pushrod straightens out (there is a spring inside) and jams
against the ramp, which then pushes it upwards. That dislodges the roller
from the notch, allowing the spring in the upper LH corner to push the lever
back to center.
Unfortunately it doesn't work very well without the cover piece to hold
things in place.
One critical and perhaps not obvious bit: the cancellation ring needs to be
in the correct position relative to the steering wheel, which in turn needs
to be centered when the wheels are straight ahead. Since the steering ratio
is so high, you rarely turn the wheel through a full revolution, and the
ramp has to be positioned where it will press against the ramps with the
small amount of movement involved. To achieve that on assembly, you first
center the steering and then turn the plate that drives the cancellation
ring to where the fingers are pointing straight down. Insert the control
head into the wheel and then tighten all 3 grub screws firmly, without
letting anything turn before they are tight.
Also, the spigots (trunnions) that hold the lever and allow it to turn need
to be lubricated in my experience. If the joint is too stiff, the springs
cannot return the lever to center. In the past, I have used "dry moly" to
lubricate the switch components, but it doesn't work as well as I hoped.
This time instead, I'm using just a tiny dab of synthetic brake grease. It
seems to be working well so far, hopefully it won't attract dirt and get
gummy over time. I used it on the switch contacts too, although Vaseline
would work just as well there.
All clear as mud? Feel free to ask ...
-- Randall
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