A.J.S. 16, Instruction Book

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NOTE—Remember there is a paper washer under each oil pump end cap and, when
fitting a new paper washer to the front cap, ensure the oil passage in the front
cap is not obstructed by the paper washer.
Important
Never attempt to insert the guide screw unless both oil pump end caps are
removed, when by moving the pump plunger to and fro with the fingers it can be
felt when the pin engages with the groove in the plunger. When correctly
fitted the shoulder on the screw will abut against the boss into which it fits.
(See illustration 4.)
Do not under any circumstances revolve the engine until quite certain that the
pin is correctly positioned otherwise damage will inevitably result.
Securely tighten the screw to prevent any possibility of it unscrewing in use.
Under no circumstances should either the pump plunger or guide screw be disturbed in ordinary
routine
maintenance.
OVERSIZE PARTS A N D REBORING CYLINDER BARREL
Pistons and rings, ·020" and ·040" larger than standard, are available. These degrees
of oversize make it essential for the cylinder barrel to be re-bored to accommodate them.
We can provide that service at prices quoted in the Spares List. See technical data
for sizes.
When the wear at the top of the barrel reaches ·008" the barrel should be bored out
·020" oversize and a new oversize piston and rings fitted.
Crankpin rollers ·001" larger than standard can be supplied. We recommend only
skilled mechanics should fit these because it is almost general that the big-end journals
and sleeves require "lapping" to ensure a correct fit.
REMOVING SPARKING PLUG—ALL MODELS
Always exercise the greatest care to avoid thread seizure when removing a sparking
plug. If any resistance is felt, apply penetrating oil. Before replacing plug, it is desirable
to coat the thread with "Oil Dag" or Graphite paste. This will guard against seizure
upon subsequent removal.
DECARBONISATION—TWINS
TO REMOVE CYLINDER HEADS
To ensure the various parts of each head are not intermixed it is recommended that only
one head is removed at a time.
Remove the petrol tank, as already described.
Remove the rocker box covers, as already described.
Remove the sparking plugs.
Remove the exhaust pipes and silencers (no need to separate pipes and silencers) by
taking away nuts and washers holding pipes to stays and silencers to rear frame, pulling
silencer end of each assembly outwards far enough to allow fixing studs to disengage and
then pulling each assembly forwards till disengaged from the cylinder head.
Remove air filter (if fitted).
Remove carburetter by taking away the two fixing bolts and withdrawing to the rear.
Lay carburetter aside.
Remove inlet manifold by taking away the four fixing nuts and washers and withdrawing
to the rear. Take care not to damage the gaskets between manifold and heads or rubber
ring insert.
Remove cylinder head steady plate (secured by 3 bolts and nuts).
Remove heads by using box spanner 015213 to remove the four nuts that retain each head.
After removal invert each head to dislodge the spacers under the nuts and lay aside to
await re-assembly.
The cylinder head gaskets will generally adhere to the tops of the barrels but care must
be taken not to damage them.
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