Royal Enfield METEOR MINOR STANDARD 1958 Workshop Maintenance Manual page 8

end of the pushrod. It flows down the push rod
into the cam tunnel where it lubricates the cams
and tappets and thence into the timing chest,
lubricating the timing chains. There are small
holes from the inlet cam tunnels through the
cylinder walls for the purpose of lubricating the
skirts of the pistons and a hole from the inlet
cam tunnel into the timing chest through which
surplus oil from the inlet rockers passes. The
exhaust cam tunnel, however, has no hole but is
kept full of oil to ensure adequate lubrication of
the exhaust cams and prevent wear. The oil
level is maintained to a height in the groove in
the tappet guide where a hole is drilled in to the
timing chest, through which surplus oil from the
exhaust rockers passes.
Both pumps are double acting, one side of
the feed pump supplying the big ends only and
the other side the rockers and valve gear. In a
similar manner one side of the return pump
pumps the big end oil back to the tank from the
crankcase and the other side the valve gear oil
back to the tank from the timing chest.
A spring loaded relief valve controls the
pressure of the oil to the valve rocker gear
which is through external pipes.
A gauze strainer is provided for the feed oil
leaving the tank and there is a large capacity felt
filter in the feed to the big ends. An aluminium
cylinder is fitted over the fixing stud inside the
filter element to reduce the volume of oil
required to fill the filter after it has been
dismantled for cleaning and to ensure the rapid
flow of oil to the big ends. A small circular
magnet is also fitted over the fixing stud inside
the oil filter for the purpose of collecting any
ferrous particles which may be suspended in the
oil.
17. Breather
The efficient operation of the breather is of
paramount importance to the performance of the
engine. It acts as a non-return valve between the
crankcase and the outside atmosphere, causing a
partial vacuum in the crankcase and rocker
boxes which prevents the passage of oil into the
cylinders and consequent smoking and oiling of
the plugs.
On early models the breather is located on
the driving side of the crankcase and consists of
a small housing attached to the crankcase by
three screws and having a short rubber tube
with flattened end, which acts as a non-return
valve.
On later models the housing contains two
pen-steel discs covering two holes drilled in the
crankcase. Accurate seating of the discs is
ensured by a pen-steel plate held between the
breather body and the crankcase.
In addition a breather, in the form of a pen
steel disc, is situated in a recess in the head of
the special bolt, which secures the alternator
rotor on to the end of the crankshaft. This bolt is
drilled throughout its length, and communicates
crankcase pressure to the breather via the hole
drilled through the drive side main journal.
A plug screwed into the head of the bolt
retains the disc, and a hole drilled in its centre
allows the crankcase to breath in to the primary
chaincase.
A vent pipe fitted to the top of the primary
chaincase has its aperture inside the case
shielded by a baffle from the oil flung from the
chain. (See section C, fig 7)
18. Gearbox
The gearbox is bolted on to the back of the
crankcase and has four speeds, which are foot
controlled, and a patented neutral finder. All
gears are in constant mesh, changes being
effected by robust dog clutches. (See Section
E).
The standard gear ratios are as follows :-
Bottom Gear
Second Gear ........ ... ... 8.42
Third Gear ........... ... ... 6.08
Top Gear .............. ... ... 4.67
19. Clutch
The clutch has 5 pressure plates and four
friction plates, including the sprocket which is
lined on both sides with friction material. The
other friction plates have Klinger inserts or/and
bonded on friction material, which give smooth
operation and freedom from slipping in the
presence of oil.
Early Late
... ... 13.00 13.00
8.60
6.37
4.67
Section B13 Page 3