Oil
– the engine oil capacity of Sunbeams is relatively small,
more so on early S7s and less so when a sump extension is fitted.
Regular checks of the oil level is a wise precaution but don't
over-fill. Good quality SAE50 mono-grade mineral engine oil is
most popular. A full oil change is advisable annually or after
about 2K miles, whichever occurs sooner. (Refer to the separate
sheet for running-in.)
Tyre
pressures – tyre pressures can affect handling
significantly and even dangerously. Preferences differ but I run
S8 tyres at 36psi and S7 tyres at 30psi. Using higher pressures
reduces drag and sharpens the handling, particularly on S7s.
Cables
– cables can last a long time but they don't last forever.
Failures are inconvenient, can be dangerous and are avoidable.
Lubricate them regularly and they work better and last longer.
Look for fraying of the inner cable near the ends and damage to
the casing that can let water in. Smooth curves are best –
sharp curves increase friction and shorten cable life.
Engine
oil leaks – Sunbeams can be prone to oil leakage, even when
the gaskets and seals are in good condition. It is usually a
result of increased crank-case pressure. Worn engines tend to
have more crank-case pressure, owing to increased 'blow-by' of
combustion gasses. Poor engine breather performance is often the
cause. Check that air is freely expelled from the breather when
the engine is idling. If you have an enclosed breather cover,
occasionally check that air cannot pass back into the breather by
blowing onto the pipe. The breather is a one-way valve so air
should flow out freely but be prevented from flowing in. The
breather pipe (where fitted) should be as short as possible and
free of constriction.
Tightening
engine fasteners – it is good to keep fasteners tight but
don't be tempted to over-tighten them in a desperate attempt to
cure an oil leak. Over-tightening can distort casings, pull
threads and make leaks worse. Instead look for the real cause,
e.g. breather malfunction, a failed seal or a damaged gasket.
Transmission
oil – keep the oil in the gearbox and the rear drive
topped-up to the level plug but never over-fill them. Leave the
level plug open for at least 1/2-hour after filling, to make sure
that the oil level is correct. It is OK to use engine oil in the
gearbox but SAE90, GL-1 gear oil works at least as well. The rear
drive requires a more viscous oil. Most people use SAE140, GL-1
to GL-3 gear oil. Under no circumstances use any gear oil rated
higher than GL-3 in either the gearbox or the rear drive because
the additives will 'eat away' the expensive bronze components.
Spannering
– is the process of checking the whole bike regularly for
loose fasteners. Over-time, fasteners can vibrate loose or they
can be accidentally left loose after maintenance. Frequent
spannering is good practice to improve safety but it can also
prevent the loss of parts that are expensive to replace. Doing it
after washing the bike can also lead to the early discovery of
poor adjustment or failing components.
Brakes
– check brake shoes at least annually for wear or oil
contamination. Where present, keep the fulcrum cones adjusted
properly for optimum brake performance. Loosen the cable adjuster
and turn the fulcrum adjuster clock-wise until the shoes just
start to bind then back them off by one click. Then adjust the
cable to your requirements.
Synthetic
oils – those owners who understand advanced oil
specifications can use appropriate modern synthetic oils for
better performance and longer life. But check carefully the
additives and recommended usage, to avoid damage.
