Royal Enfield CONSTELLATION 1958, Workshop Maintenance Manual

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eliminates pockets and sharp edges and allows a
smooth flow of gas without eddies.
If the inlet valves or their seats are pitted and
require recutting, care must be taken to
reproduce the correct profile as shown in Fig. 8.
The cylinder heads should preferably be
returned to the works for the inlet valve seats to
be re-cut, but, if this is not possible, a special
tool consisting of an arbor No. T 2053 and cutter
No. T 2054 is available. Great care must be
exercised in using this tool, as it is located off
the valve guides and these may be damaged if
suitable apparatus is not employed.
The inlet valve faces and seats can be cut at
45 degrees in cases of expediency but this may
have a deleterious effect on the performance of
the engine.
19. Re-Assembly after Decarbonising
Before building up the engine, see that all
parts are scrupulously clean and place them
conveniently to hand on a clean sheet of brown
paper.
It is advisable to fit new gaskets to the
cylinder base and cylinder head. Two paper
gaskets are fitted to the base of each cylinder.
Smear clean oil over the pistons, having
replaced the rings if these have been removed,
lower the piston over the connecting rod and
insert the gudgeon pin from the outer side. Fit
the circlip and then fit the second piston in a
similar manner.
Check the piston ring gaps to find out
whether excessive wear has taken place (see
Subsection 17).
Oil the cylinder bores and lower the barrels
over the pistons and seat them gently on their
gaskets.
Drop the push rods down their tunnels on to
the tappet heads, shallow cups upwards.
Fit the copper cylinder head gaskets and see
that the dowels are in position.
Replace the cylinder heads as described in
Subsection 10.
After the engine has been assembled, run it
for a brief period at a speed which will ensure
that the ignition has been advanced by the
automatic advance device. If it is run too slowly
"blueing" of the exhaust pipes may take place.
After the engine has been run for some time
and has become thoroughly hot, go over all the
cylinder head and other nuts to ensure that they
are tight.
20. Cleaning the Oil Filters
The oil filter is located in the timing cover
immediately below the oil pumps and is in the
feed circuit to the big ends.
The filter element is removed by unscrewing
the nut holding the end cap in position. When
re-assembling the filter after cleaning, take care
that no grit or other foreign matter is sticking to
it. The aluminium cylinder fitted over the rod
inside the filter element is to reduce the free
space which has to be filled after cleaning
before oil reaches the big ends. After emptying
the filter chamber it is essential to run the
engine slowly for about five minutes to ensure
that oil is reaching the big ends.
The felt element should be taken out and
washed in petrol after the first 500 miles and
after every subsequent 2,000 miles. Fit a new
element every 5,000 miles.
21. Overhaul of Oil Pumps
Remove the timing cover as described in
Subsection 1.
Remove the end plates from both pumps.
Remove the pump discs and plungers.
Remove the pump spindle which can be
pulled out from the front or return pump end.
Section C4 Page 7
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