Norton 19S - Maintenance of Engine

carrying oil to the half-time pinion and the
timing gears.
A further timed breather is incorporated in
the driving side mainshaft and releases pres-
sure through a small hole in the underside of
the mainshaft bearing boss.
A lead is taken from the oil return pipe to
a banjo fitting on the rocker box, feeding oil
to the rocker shafts and ball ends. Surplus
oil returns down the pushrod cover tubes to
the crankcase. Excess oil from the O.H.V.
valve spring chambers drains back through
drilled holes in the cylinder head and barrel.
Oil is fed to the magdyno chain by passing
through the inlet cam spindle bush into the
chain case. Any excess of oil accumulated in
the case, drains through the breather pipe.
Crankcase pressure is released by a valve on
the driving side of the crankcase and oil mist
is fed to the rear chain.
All the oil drains to the base of the crank-
case to the sludge-trap, is picked up by the
suction of the return side of the pump and
returned to the tank.
The oil-way from the sludge-trap is situated
so that any foreign matter is left in the trap.
This
leaves the case when the crankcase drain
plug is removed and the oil drained.
MAINTENANCE
OF ENGINE
DECARBONISING
6. REMOVAL OF PETROL TANK.
It is not necessary to drain tank, but make
sure that the petrol tap levers are in the " Off "
position, that is, with the round end of the
lever pressed in.
Disconnect petrol
pipes from taps. Use two
spanners, holding the union nut with one, and
the tap union with the other.
Remove the four bolts and washers, and the
tank is free from the frame.
Four shouldered rubber washers and steel
washers should be on the tank brackets.
The
order in which rhe washers for rhe
rank mounting should be placed. (Fig. 4)
9
7. Fl'l1.'ING OF TANK.
Place the four shouldered rubber washers
on the frame tank brackets, with the steel
washers above.
Place tank in position and fit cupped steel
and rubber washers on to the tank bolts.
(Fig. 4).
Fit bolts to tank and tighten down evenly.
Ensure that the tank is clear of the frame.
Fit petrol pipes, using the two spanners as
when removing.
8. REMOVAL OF CARBON.
Scrape carbon from top of piston and
cylinder head.
Both are of the alloy type and care must be:
taken not to damage them
Place an old piston ring at the top of the
bore, and resting on top of the piston. It will
prevent the carbon being removed at the edge
of the piston and end of the bore.
After an engine has been used for any con-
siderable time, wear in the bore and ·the rings
takes place, allowing a small amount of oil
to pass.
The carbon on the piston edge and the top
of the bore acts as an oil seal and if removed,
engine may use a little more oil until carbon
is re-formed.
The carbon deposit in the valve ports and
valve spring compartment cannot be removed
unless the valves are tcmoved.
Valves need NOT be removed at every
de-carbonisation.