ASSEMBLING
THE ENGINE
Before commencing this operation, clean down the work bench and lay out the
engine units and parts in assembly order. Also check the nuts, bolts and washers.
etc., and have the gaskets and jointing compound available. When the engine is
being erected, each working surface must be liberally oiled. This can be done with
the use of a clean paint brush or an oil can. The operator should not rub on the
oil with his fingers, otherwise a certain amount of grit, etc., may be picked up during
the process.
Crankcase, Driving Side. Lubricate the main bearing and the camshaft bushes.
Crankshaft Assembly. Enter the driving side shaft into the ball-race in the drive
side crankcase.
Ensure that the shaft
is
fully located.
(it
is
advantageous to allow
the shaft to protrude vertically through a convenient hole in the bench and then the
outer face of the drive side crankcase will take the weight on the flat surface of
the bench).
Camshaft.
As both camshafts are identical, the mechanical breather can be fitted
into either.
First insert the spring and then the breather disc valve engaging the
projections into the camshaft slots. Enter this assembly into the inlet (rear of
engine) camshaft bush and test the engagement of the disc valve by depressing the
camshaft. Insert the other camshaft into the exhaust (front of engine) camshaft bush.
Crankcase Timing Side.
Lubricate the main bearing and camshaft bushes.
Lightly smear jointing compound on the inner mating face, then thread this half
over the crankshafts and camshafts. Bolt the two halves together, ensuring that
these meet without undue force being applied. If any difficulty
is
encountered,
suspect the breather disc in the inlet camshaft being out of position. To remedy,
rotate the camshaft until the slot
is
engaged. Two internal screws are located in
the crankcase just above the camshaft
;
be sure to replace these.
Aligning the Crankcase Halves. The top of the crankcase must present
a
perfectly
flat
face to the cylinder base. There must be no step between the halves.
If
a
step
is
evident, a sharp tap on the stud boss nearest to the proud face, with
a
hide hammer, will bring
it
flush.
Do not strike the base face itself. When the two
faces are properly mated, the bolts and screws should be fully tightened.
Rotate
the crankshaft to check for freedom of movement.
Sump Filter.
Fit the filter with a new joint washer to the sump and over the
scavenge pipe, then the cover with a joint washer.
Replace the four washers and
nuts but do not over-tighten, otherwise a broken stud may result, a trouble which
can be well avoided
at
this stage.
Crankcase.
Place the crankcase in the vice
as
in the dismantling procedure
pour into
it
an egg-cupful of engine oil.
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