Royal Enfield 500 TWIN 1949 Workshop Maintenance Manual page 44

ROYAL ENFIELD WORKSHOP MANUAL
2 (f). Contact Breaker Spring
The correct contact breaker spring pressure,
measured at the contacts, is 18-24 oz.
3. Testing Magdyno in Position on Engine
To locate cause of misfiring or failure of
ignition, check as follows:
(i) Remove the sparking plugs from the
engine. Hold the ends of the H.T. cables about
1/8 in. from the cylinder block and crank the
engine. If strong and regular sparking is
produced the fault lies with the sparking plug or
plugs which must be cleaned and adjusted or
renewed.
(ii) If no sparking is produced at either H.T.
cable, examine the faulty cable and, if
necessary, renew it as described above in
Subsection 2 (d).
(iii) Very occasionally the fault may be due
to a cracked or punctured pick-up moulding.
This type of fault is not easily detected by
inspection and a check should be made by
substitution.
(iv) If an ignition cut-out switch is fitted,
disconnect the cable at the magneto and retest. If
the Magdyno now functions normally the fault is
in either the cable or the cutout switch. Correct
by replacement.
(v) If the Magdyno has recently been
replaced or removed, it may be incorrectly
timed (see Section C1, Subsection 4.)
(vi) Check the contact breaker for cleanliness
and correct contact setting as described in
Subsection 2 (a).
If the cause of faulty operation cannot be
traced from the foregoing checks, the cause may
be an internal defect in the Magdyno. The
Magdyno should therefore be removed from the
engine for attention by a Lucas Agent.
Section G1b Page 3