Manual Timing Device
If the magneto gear has been taken off always refit it loosely on the armature. On early models the magneto gear centre acts as a part of the crank case release or breather, and must therefore be correctly timed in relation to the piston, on these machines the gear is marked for re-fitting purposes.
Next set the piston (this setting applies only to machines with Lever Ignition Control), before top dead centre (40 degrees before top centre if a timing disc is used) of the compression stroke and set the control lever on the handlebar to the fully advanced position (see below for details of Retiming when Automatic Timing Device is fitted). The contact breaker points must be correctly adjusted to the gauge (correct gap .012"). Rotate the magneto armature until the contact breaker points are just separating and tighten the magneto gear nut, being careful not to move the armature in relation to the gear when so doing.
To find top centre of the compression stroke take off the inlet rocker cover and take out the sparking plug. Turn the engine forward slowly until the inlet valve is seen to open and close. Insert a cycle spoke or stiff wire through the sparking plug hole and turn the engine very slowly forward until the piston reaches its highest point in the cylinder which may be felt by means of the spoke. Now turn the crankshaft slightly backwards until the correct position for setting the magneto is obtained.
NOTE. On all machines where the breather pipe leads from the crankcase behind the cylinder to the rear chain or on machines later than 1936 the position of the magneto gear in relation to the piston is immaterial as long as the magneto timing is correct.
Details of Retiming when Automatic Timing device is fitted.
On machines fitted with Automatic Ignition Control no manual control lever is provided. The device does not require any attention or adjustment.
Should it be necessary to remove the magneto, the gear and timing device are removed exactly as described above.
Do not under any circumstances take the device to pieces, or attempt to remove it from the gear wheel.
When retiming the magneto, refit the centre so that it is just free on the armature, see that the device is held retarded (the spring incorporated automatically returns the mechanism to this position), and set the contact breaker points to separate 14 degrees before the top dead centre of the compression stroke.
It is essential to use a timing disc on the crankshaft for re-setting. When correctly set, tighten nut and re-check. By the courtesy of Messrs. C. C. Wakefield & Co., Ltd., we can supply a Wakefield Timing Disc free of charge, except for 2d. postage.