ISOLASTICS: The front Mk III units can he fitted to any/all of the earlier models but the centre tube has to
be shortened so that both ends are the same length, preferably by machining (as opposed to hack saw)
to keep the ends square. The rear Mk III unit is not really worth the effort and expense of fitting. The
adjuster rods for the Isolastic have been known to rust up so a check-strip and grease would be
advisable.
SWINGING ARM LUBRICATION: The "sealing for life" of these units is not adequate so modification can
be made to allow lubrication: - Remove right-hand end cap, remove spindle and all wicks except far left
wick, Drill right-hand end cover and tap ; UNF to take a grease nipple. Right-hand disc wick needs } hole
through middle as well. Drill two 1/8 in holes diagonally right through spindle 1/2 in from each end.
Replace spindle disc wick with hole, and end cap with nipple and fill assembly with light oil (Castrolite)
from grease gun. Lubricate regularly. Castrolite is not always available in which case a useable
alternative, especially in primary chaincases, is Castrol 4 stroke oil (made for Hondas) GP 10-40.
SERVICE RELEASE No. N3/13: ( Camshaft Interchangeability on 1974 and 1971 Commando (all
models). Camshaft/Crankcases/Cylinder heads and valves are affected.)
Following the introduction of new crankcases with modified breathing, together with the introduction of the
Combat "SS" type crankshaft, there are now several possible combinations of crankcases and camshafts.
In addition, where it is desired to fit the high performance "SS" type crankshaft to a Pre-1972 engine there
are problem, with cam lobe clearance at the crankcase oil fling shroud, In addition, problems can arise
due to valve head diameter, valve stem and spring length discrepancies, particularly where an early "non
Combat" cylinder head is fitted.
It is also essential to fit tappet locating plates 063092 to accommodate the increased lift on both
"SS" and "SSS" camshafts.
The part numbers and applications of the various components are tabled below
Cam Part
Number
Identification
Stamped on
Journal
Type
Use Part
Number
Comments
061084 S Scrolled 061084 Standard 1971 plain bushes
062608 S Plain 061084 Standard 1972 scrolled bushes
062671 SS Plain 063536+ Combat 1972 scrolled hushes
062807 SS Scrolled 063536+ Combat 1972 plain bushes
063536* SS Scrolled 063536+ Combat 1972 plain bushes
063537* SS Plain 063536+ Combat 1972 scrolled bushes
TW0302 SSS Scrolled 063761+ Original NVPS camshaft, plain bushes
063453* 5SS Plain 063376+ Variant TX0302 scrolled bushes
063761* SS
lain bushes
Use scrolled journal camshafts prior to Engine Number 204048 with plain bushes NMT2036 & NMT2037.
Use plain or scrolled journal camshafts subsequent to Engine Number 204049 with scrolled bushes
062600.
Note: Scrolled condition camshafts only will be supplied against order for the above camshafts.
'Surface treatment
+Conversion from standard cams to Combat condition requires the following
a) Cylinder head 063327 to provide 10:1 compression ratio.
b) Solid skirt Combat pistons (063348 L.H. 063349 RH, Std.)--See Service Release N.2/4 for oversizes.
c) Combat valves - inlet 063283, exhaust 063282.
d) Standard valve springs NM22838 outer, NM22839 inner using spring seat and spacers to provide
0.050 in. (1.27mm) clearance at full lift.
+e) Conversion to "SSS" specification - as Combat from standard
--- no further action required for Combat.
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