|
9
|
Rotate the engine backwards gently until the
machined mark on the rotor registers with 28°
on the indicator plate. At this precise moment the
contact breaker points should start to open in
which case timing is correct.
|
|
|
|
The exact point of separation can be determined
by inserting a strip of very thin paper between the
points. The points will grip the paper when closed.
By moving the engine slowly, a light pull on the
paper will dislodge this at the exact point of
separation. Take care not to leave a shred of paper
between the points when using this method. A
preferable method is to use a low wattage bulb and
holder with a short length of wire attached to the
bulb body with a second length of wire attached to
the bulb connection. Crocodile clips should be
attached to the loose end of both wires. Connect
one wire to the contact breaker spring of the set
of points being checked and the second wire to a
suitable earth point on the engine. Switch on the
ignition and as the engine is turned, the bulb will
light at the exact point of separation.
|
|
|
|
10
|
If the timing is incorrect, i.e. the points do
not open at 28° before T.D.C., release the two
screws in elongated holes which secure the main
backplate and rotate it in the housing. To advance
the timing, move the baseplate clockwise and to
retard, move the baseplate anti-clockwise. When the
timing is correct, secure the backplate screws.
|
|
11
|
Using the same technique, check that the
contact breaker points open at 28° B.T.D.C. on
the firing stroke for the second cylinder. If
incorrect, make adjustment by movement of the
secondary backplate. To do so, slacken screws (A)
in Fig. C47 and use the eccentric headed adjusting
screws (B) to move the mounting plate. When timing
is correct, re-secure the screws (A).
|
|
|
|
Ignition Timing Procedure - Engine
Running
|
|
|
|
(Stroboscope Method)
|
|
|
|
This method is greatly preferred for extreme
accuracy in setting. Prior to checking timing,
clean and set both sets of contact breaker points
to the figure given in "General Data."
|
|
|
|
Note that late models have two marks on the
rotor but that if the ignition timing is
sufficiently correct for the engine to run at all,
the stroboscope will only detect the correct
marking. If the engine has been rebuilt and
ignition timing is being set from scratch, firstly
follow the basic procedure in the preceding text.
Commence stroboscopic timing as follows:
|
|
|
|
1
|
Remove the inspection cap on the chaincase to
reveal the degree indicator plate and timing mark
on the rotor.
|
|
2
|
Connect the stroboscope to the H.T. lead on the
right cylinder and use a battery separate to that
on the motorcycle to power the lamp, thus
eliminating possible incorrect readings. For the
full method of connection follow the stroboscope
lamp manufacturer's instructions.
|
|
3
|
Identify by lead colours the set of contact
breaker points on which timing is being set by the
colour of the wiring at the points and the ignition
coil.
|
|
4
|
Start the engine and run at a steady 3000 r.p.m.
indicated on the tachometer.
|
|
5
|
Shine the stroboscope lamp on the indicator
plate. If timing is correct, the rotor marking will
register with the 28° marking on the indicator
plate. If the marks do not align, the timing must
be adjusted.
|
|
6
|
To adjust the timing at the first set of points,
release the two screws in elongated holes which
secure the backplate and rotate it in the housing.
To advance the timing, move the baseplate
clock-wise and to retard, move the baseplate
anti-clockwise. Move the backplate on its slots
until the rotor mark and 28° marks align when
checked with the stroboscope then secure the
backplate screws.
|
|
7
|
Reconnect the stroboscope for the left cylinde
and again check for rotor mark alignment at
28°.
|
|
8
|
If timing is incorrect for the left cylinder,
correct by slackening off the clamping screw for
the secondary backplate for this set of points then
use the eccentric headed adjusting screw to move
the secondary backplate (see Fig. C47-secondary
backplate screws are marked "A" and eccentric
screws are marked "B"). Recheck timing with the
stroboscope and when correct, secure the screws
"A".
|
|