Royal Enfield METEOR MINOR STANDARD 1958 Workshop Maintenance Manual page 14

until the last coil is 1 to 1.1/2 threads below the
top face. Then break off the tag.
If the cylinder head has been removed, the
fitting of the insert will be facilitated if the tool
is put through the hole from the inside and the
insert screwed back from the outside.
If the cylinder head has not been removed,
care must be taken not to drop the end of the tag
into the cylinder and in such a case it is better to
break off the tag with a pair of long-nosed pliers.
Note: Some engines have short-reach plugs,
in which case wire inserts are fitted as standard.
15. Removal of the Cylinders
When the cylinder heads have been removed
the cylinders can be lifted clear of the studs.
This should be done with the pistons at top dead
centre.
It is advisable to put a clean cloth over the
mouth of the crankcase to prevent anything,
such as a piece of broken piston ring, from
falling in.
When replacing the cylinders, clean off the
joint faces and fit new paper joints, two to each
cylinder.
16. Removal of Pistons
Remove the cylinder heads and cylinders.
With a tang of a file remove the two outer
circlips retaining the gudgeon pins. Remove the
long central cylinder studs which come opposite
the gudgeon pins.
Use Special Tool No. E.5477 to extract the
gudgeon pin or using a rod about ¼ in. in
diameter insert this right through one gudgeon
pin and drive the other pin out of its piston,
supporting the connecting rod substantially
meanwhile to prevent distortion.
Having lifted the first piston away, the other
one may be readily removed in the same
manner. Mark the pistons and gudgeon pins so
that they go back into the same pistons the same
way round and so that the pistons go back into
the same barrels the same way round.
Take care not to drop the gudgeon pin
circlip into the crankcase. A clean cloth should
be put over the mouths of the crankcase to
prevent this.
17. Decarbonising
Having removed the cylinder heads as
described in Subsection 10, scrape away all
carbon, bearing in mind that you are dealing with
aluminium which is easily damaged. Scrape
gently and avoid scoring the combustion
chamber or the valve seats which are of
austenitic iron shrunk into the head. Be careful
while performing this work not to injure the joint
faces which bed down on to the head gaskets.
Do not, in any circumstances, use caustic
REMOVAL OF PISTONS
soda or potash for the removal of carbon from
aluminium alloy.
Scrape away all carbon from the valve heads
and beneath the heads, being very careful not to
cause any damage to the valve faces.
If the piston rings are removed the grooves
should be cleaned out and new rings fitted. For
cleaning the grooves, a piece of discarded ring
thrust into a wooden handle and filed to a chisel
point is a useful tool.
If the piston ring gaps exceed 1/16 in. when
the rings are in position in the barrel, new rings
should be fitted. The correct gap for new rings is
.011-.015 in. The gap should be measured in the
least worn part of the cylinder, which will be
found to be the extreme top or bottom of the
bore.
While the cylinders and pistons are not in
position on the engine, cover the crankcase with
a clean cloth to prevent the ingress of dust and
dirt of all kinds. Do not, of course, attempt to
scrape the carbon from the pistons when the
mouths of the crankcase are open.
Fig. 5
Section C13 Page 5