AJS 350 1954, Maintenance Manual And Instruction Book, Page: 36 / 96

TO RE-TIME THE IGNITION
The normal advance is 37° (
v
") max permissible 39° (½").
Have available a stout screwdriver, or an old type tyre lever with turned up end, also a
small rod or stout wheel spoke 5½" long.
Before setting the ignition firing point it is essential the magneto contact breaker points
are correctly adjusted. Therefore always check these first.
Check contact breaker points by :
Remove contact breaker cover.
Check setting of contact breaker points, and, if necessary, re-set same.
Set ignition firing point by :
Remove :—
The sparking plug high tension cable from plug.
The sparking plug.
The magneto chain case cover.
The rocker box side cover.
Unscrew, several turns, nut retaining magneto sprocket to camshaft. (No need to remove
nut).
Lever off sprocket until it is loose on the taper of the shaft. (Use stout screw-driver
or old type tyre lever.)
Turn over engine till both valves are closed.
Insert rod through sparking plug hole, feel piston, by rocking engine forwards or
backwards till it is felt the piston is at the top of its stroke with both valves closed.
Mark rod flush with top face of sparking plug hole. Remove rod and measure
v
" above
the flush mark and record position on rod.
On 350 c.c. models place the handlebar ignition control lever in the fully advanced
position.
On 500 c.c. models turn the front plate of the automatic unit with the fingers and thumb
to its limit of movement and insert a wood wedge to hold the control in the fully
advanced position.
Replace rod in sparking plug hole.
Slightly rotate engine BACKWARDS until upper mark on rod is flush with top face
of sparking plug hole. (To rotate engine, engage top gear and turn back wheel by hand.)
Rotate sprocket on magneto armature shaft, in anti-clockwise direction (as seen from
sprocket end of magneto), till the contact breaker points are just about to separate.
(To find the exact moment for the commencement of the point separation, place a piece
of tissue paper between the points and turn the armature shaft (by the sprocket on it)
until the paper is just released, and no more, upon a gentle pull.)
Tighten nut on camshaft and ensure engine, and/or magneto shaft, does not move in
doing so,
Re-check the setting which must be
v
" before top dead centre. (With the ignition
fully advanced.)
Do not omit to remove the wood wedge securing the automatic unit on 500 c.c. models
in the fully advanced position before refitting the chain cover.
See page 89 for particulars of special timing disc graduated in degrees.
Replace
Rocker box side cover, Contact breaker cover, Magneto chain case cover, Sparking
plug (see note on page 36 re graphite on sparking plug thread), and Sparking plug wire.
34