A.J.S. 16, Instruction Book

Page: 35 / 104

Replace the cylinder head by:
Carefully clean the top edge of the cylinder barrel and the under face of the cylinder
head.
Fit the cover tubes, with their rubber gaskets and metal washers, into the cylinder
head.
Place the cylinder head gasket in position on the top edge of the cylinder barrel.
Place a rubber gland round each tappet guide.
Place the cylinder head in position.
Ensure each cylinder head securing bolt has a plain steel washer on it and then replace
the bolts and engage each a few turns.
Finally, screw down the cylinder head securing bolts, in turn, bit by bit, until all are fully
home.
Replace
The sparking plug, but before doing so it is desirable to coat thread with " O i l Dag" or
graphite paste to prevent seizure upon next removal.
The rocker box, carburetter, exhaust system, and the petrol tank.
NOTE—If old gaskets are re-fitted they must be in an undamaged state otherwise new
must be used.
Whether new or re-used, the gasket should be annealed just prior to fitting. This is
done by heating to "blood red heat" and plunging into clean cold water.
TO REMOVE T H E CYLINDER BARREL A N D PISTON
Remove
The cylinder head.
The four nuts retaining cylinder barrel to crankcase.
Take away
Cylinder barrel. (Ensure piston is not damaged in doing this. Steady piston with hand
as barrel is withdrawn.)
Fill throat of crankcase with clean rag to prevent entry of foreign matter.
Remove
One gudgeon pin circlip. It is immaterial which circlip is removed. Use special pliers
included in tool kit.
Gudgeon pin by pushing it out of piston.
Take away piston.
NOTE—The gudgeon pin is an easy sliding fit in both piston and connecting rod small-end
bush.
Rings may be removed from a. piston by introducing behind the rings three
pieces of thin steel spaced at 120° from each other and then sliding off the rings.
(Do not scratch the piston.)
TO REPLACE T H E PISTON A N D CYLINDER BARREL
All parts must be clean.
Place rings on piston, scraper first then the two compression rings. On all models the
top compression ring is chromium plated.
These chrome plated rings have a slightly tapered exterior and when new are clearly
marked with the word TOP on one side to indicate assembly position. After use this
word tends to become indiscernible, but over a large mileage the assembly position can
be determined by brightness of the edge contacting cylinder wall. This bright edge is
the lower one. When as the result of wear, contact with the cylinder wall appears
uniform over the whole width of the ring, it is then immaterial which way round it is
re-fitted.
Smear gudgeon pin with engine oil.
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