Monday 4 August 2008
There is a ritual to starting up an old
motorcycle. The sooner it is learnt, the less you feel like you are at the
mercy of unseen forces, waiting hopefully for the fortuitous alignment of
the stars and for that magic moment to occur when the engine comes to life.
This weekend's relatively successful efforts in the shed
brought back memories. My 1931 Lion has been a poor starter from the time I
bought it - and I thought naively it was the poor chump demonstrating it for
me! A year or so ago I went looking at a Model 8 from the late '20s being offered
for sale. The owner told me he had set it up just as the racers used to with
no advance/retard lever or
air lever - everything set 'just right'. Petrol on, gear lever into
first gear and, after walking it for a half-dozen paces, the valve-lifter
simply had to be
dropped. It started up a treat! The owner demonstrated it successfully. I tried it and it
owner did it again, before taking off around the block. When he returned,
complete with wide grin, he decided he wasn't going to sell after all! Oh well. nice chap,
great bike and an afternoon chatting about 'Beams.
So, back to my experiences with an obstinate Lion.
Dusting down my notes gathered from a few sources, here's how I tried
to unravel just how to get the blasted thing going ... plus some thoughts
from subsequent experience. Good luck!
'The Book of the Sunbeam'
(1945 first edition reprint,
Pitman seemed the obvious starting
point. In summary, the advice is:-
Turn on petrol tap and depress
Open throttle lever by 1/6th to
Using the exhaust lifter, smartly
depress the kick-starter (on 1939 500 and 600 c.c. Lion side-valve models,
do not forget to first raise the compressor).
That's about it, although it does continue
helpfully with the following elaboration:
"There is a certain knack in this
which one acquires in time. The points to remember are, not to open the
throttle lever too far and to release the exhaust valve lifter when the
kick-starter has completed about two-thirds of its travel. On no account
have the ignition lever more than one-half open. If this precaution is
neglected, the kick-starter mechanism may be damaged by the engine
back-firing. Should the kick-starter not engage, or appear to stick, engage
first gear and move the machine slightly, when it will free itself. Jumping
on the kick-starter crank will only damage the ratchet pinion. When the
engine has fired, open the throttle lever slightly, and after the engine has
run for a few minutes, the air lever may be opened fully and should remain
so unless starting from cold."
(2) John Marston
Ltd: 'Sunbeam Motor Cycle Manual', 1932
Some copies of the factory's manuals
refer to starting up, and some don't. Here's the advice from the 1932
manual in full:
"Easy starting is mainly a matter of
familiarity with one's motor cycle, but it is necessary that everything
should be in good order. Two very important points are: (1) the ignition
lever must be retarded, otherwise backfires will occur which might
cause damage to the starter mechanism; and (2) the throttle lever
must not be opened too wide, since the smaller the opening the greater the
suction in the carburetter. Usually the ignition lever should be retarded
one-half of its full range, and on machines with specially advanced timing
for sporting or racing purposes it may be necessary to retard as much as
two-thirds of the range to prevent backfiring. The air lever should be set
closed when starting from cold but full open for starting when the engine is
warm. The throttle lever should be opened very slightly, but the exact
position for best results is a matter for experiment. Then turn on the
petrol and slightly flood the carburetter if starting from cold. This,
however, should be omitted if starting when the engine is warm. Raise the
exhaust valve lifter lever and press down the starter pedal. If the teeth of
the starter do not engage at the first attempt, do not use force but move
the machine slightly whilst in gear. This will allow the teeth of the
starter mechanism to engage. If the engine is stiff, operate the starter a
few times till the engine is felt to be moving freely. Then give a final
swing to the starter, at the same time releasing the valve lifter, and keep
the starter at the bottom of the stroke until the engine fires. In the event
of a backfire this will prevent damage to kickstarter mechanism.
"If there is any difficulty in getting the engine to
fire, look for the trouble amongst some of the following:
Over-lubrication which causes the piston to
Points of the sparking plug too far apart. The
correct distance is about twenty-five thousandths of an inch.
Alternatively, if the points are bridged by carbon or
oil, the plug must be cleaned.
Platinum points of magneto dirty or too far
apart. The points should be set to a gauge supplied by the manufacturers
and included in the tool kit.
Do not alter the setting of the carburetter
unless you are positive the fault lies here. The carburetter is carefully
adjusted before the machine leaves the works.
A choked jet or water in the carburetter.
Clean as detailed directions in carburetter handbook.
"Another form of failure is not dropping the exhaust
valve lifter early enough in the stroke of the starter. Avoid spasmodic
kicks when using the starter, since these fail to attain the desired result.
A smooth swing with the valve lifter dropped halfway through is the most
"For plugs we recommend Lodge H.1 for Models 9, 10 and
Lion and Lodge H.51 for Model 90. Racing and severe trials riding require
special consideration beyond the scope of this manual."
'Motor Cycles and How to Manage Them' (1936, p.122)
Contemporary advice from the 26th
edition (completely rewritten we are told!) of this classic guide for motorcyclists provides helpful advice for starting up late-vintage machines. Written
with the Amal Standard (pre-Monobloc) carburetter in mind, it advises:
"Now, assuming that the gear lever
is in neutral - that is, the position between bottom and second gears that
allows the machine to be pushed along without the engine revolving - turn on
the petrol and, if the engine is cold, press down the little tickler knob to
be found on the top of the float chamber of the carburetter.
"Press down the tickler until petrol
just starts to exude from the instrument; do not flood the carburetter so
that petrol drips profusely. Then place the ignition control roughly in its
mid-position. Shut, or nearly shut, the air control and open the throttle
about about a quarter of its total movement.
"Next grasp the exhaust-valve lifter
(or compression release), assuming one is fitted. Place a foot on the
kick-starter and give the pedal two or three long, swinging pushes. As the
pedal almost reaches the bottom of its travel on, say, the third kick, let
go the exhaust-valve lifter. The engine should start. If it does not fire,
the reason probably is that the valve lifter was dropped either too early or
too late, or that the so-called 'kick' was not of the swinging variety.
"Once the engine is running, open
the air lever as far as is possible consistent with the engine running
(4) And finally,
advice from an 'old hand'
Ray Jones from the Marston Heritage
Trust wrote a piece for the Marston Sunbeam Register Newsletter, May 2002
entitled 'Tips for the
Novice: Starting a ‘Classic’. Follow the link to read the article.
I found Ray's advice very
helpful. It is written from the perspective of a motorcyclist
grappling with the real life experience of their machine, rather than impersonal
instruction. And, it seems it was written following an episode when even he
too had problems starting up his machine (also written up as a short piece in the
Newsletter, which is included for light relief).
From my own perspective, the 'knack'
between achieving a heart-lifting 'bang' and a demoralising silence, rested
on use of the valve lifter - a point made in the Marston's manual. Experience, gained from long sessions of
failure, taught me that my most common failing, when everything else was set
up right, was to drop the valve lifter much too late.
Running 'n' Riding