Royal Enfield CONSTELLATION 1958, Workshop Maintenance Manual

Page: 65 / 106

Clean the electrodes, the spaces between the
electrodes and see that the carbon brush is clean
and moves freely in its holder. Clean the outside
of the cover before replacing it.
(ii) Examine the contact breaker. If the
contacts are burnt or dirty, clean them by
polishing with a very fine carborundum stone or
fine emery cloth. The contacts may be cleaned
more easily if the moving contact assembly is
removed, as Sub-section 2 (a) (ii).
(c) Adjusting Contact Breaker
After cleaning check the gap between the
contacts. Turn the engine until the contacts show
the maximum opening which should measure
0.010 in. to 0.012 in. If the setting is incorrect,
slacken
the two screws securing the
fixed-contact plate and move the plate until the
correct gap is obtained. Tighten the securing
screws and measure the gap again. Check the
gap for the other position of the engine giving
maximum opening of the contacts. Refit the
distributor gear so that the marked teeth of the
gear and of the drive engage, retighten the gear
retaining screw.
During the first 20 hours running of a new
magneto or replacement contact set, most of the
bedding down of the contact breaker heel occurs.
The contact breaker gap should, therefore, be
checked and, if necessary, reset as described
above.
(d) Replacement of High Tension Cables
Use 7 mm. P.V.C. or neoprene-covered
rubber insulated ignition cable for the high
tension leads. When connecting a new cable to
the magneto do not bare the cable but cut it off
flush to the required length. Remove the
moulded cover, slacken the cable retaining screw
and pull out the old cable. Push the new cable
fully home and secure by tightening the screw.
The pointed end of this will pierce the insulation,
make contact with the cable core and lock the
cable in place. After fitting a high tension cable a
continuity test should be made between the
cover electrode and plug end of the cable.
3. Servicing
To locate cause of misfiring or failure of
ignition, check as follows:-
MAGNETO MODEL SR2 WITH COVER REMOVED
Fig. 2
(i) Remove the sparking plugs from the
engine. Hold the end of each high tension cable
about 1/8 in. from the cylinder block and operate
the kickstarter. If strong and regular sparking is
produced the sparking plugs should be cleaned
and adjusted.
(ii) If no sparking is produced, examine the
high tension cable and if necessary renew it as
described in Sub-section 2(d).
(iii) Disconnect the cable to the cut-out
switch at the magneto and re-test. If the magneto
now functions normally the defect is in either
the cable or the cut-out switch. Correct by
replacement.
NOTE.-In no circumstances must the contact
breaker cam be removed from or turned on the
spindle. The cam is correctly positioned when
the magneto is built and the performance of the
instrument depends on this position being
maintained.
4. Automatic Advance Mechanism
This is automatically lubricated and requires
no attention beyond making sure that it operates
freely and the springs are securely fastened. For
timing instructions see Section C4, Subsection
4.
Section G1d Page 2
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