Article supplied by Peter Lawrence on trouble shooting the Boyer Bransden Ignition system
normally produces very good quality
bright blue sparks at the plugs, due to
the combination of the high quality
modern design of ignition coil and the
ignition unit, which is matched to it.
The most likely cause of weak sparks is
a poor 12-volt supply to the ignition
unit & coil. This could be a bad
electrical connection, poor switch
contacts, bad earth or discharged/faulty
battery. You can connect the positive
terminal of the ignition coil directly
to the battery positive (preferably via
an 8amp fuse), no relay required. The
ignition switch would then feed +12
volts to just the ignition only (red
wire). Wiring the ignition this way
helps overcome poor switches / poor
connections, but it is preferable to
trace the problem and rectify it.
electronic ignition it is not uncommon
to experience a slight increase in idle
speed due to improved combustion.
Adjusting the idle setting on the
carburettor(s) should rectify
The working voltage
range for our ignition units is 10 to 16
volts. The ignition coil is switched
with high current pulses (approx. 6
amps) for a short period; the average
current draw is approx. 1 amp. The
static current (engine not running) is
We hope that the
above information is of help in solving
Boyer Bransden Electronics Ltd.
FINDING BOYER BRANSDEN IGNITIONS
NO SPARK CHECK :-
BATTERY HAS POWER. (Switch
on headlamp, this should stay bright for
THE FUSE KEEPS
BLOWING. Replace the fuse with a 21 watt indicator bulb. As the
electrical circuits are switched on the
bulb will glow dimly, if a faulty
circuit is connected the bulb will glow
brightly. If the bulb glows bright with
nothing switched on, remove wires from
components in turn until the bulb goes
out, the last one removed will be the
area of the faulty circuit.
IGNITION UNIT HAS
POWER. Using a bulb or voltmeter check the main power feed in to the
ignition unit. This would be the wire
from the ignition switch or kill switch. A
21 watt indicator bulb with wires
attached makes a very good test lamp.
With this connected between the frame
and ignition feed wire, the lamp should
glow brightly, if dim or varying try
moving the fuse holder, wiring,
handlebars, to locate any faulty
connections. Also test between the feed
wire and the wire used to ground or
earth the system, as a poor earth
connection can be most difficult to
The bulb draws similar current to
the ignition and is a more useful test
than the voltmeter only.
THE UNIT HAS POWER Most
MKlll ignition units will produce a
spark on switching on and off, if this
is so and sparks are produced on all
cylinders then the ignition coils must
be in good order. If
one or more fail to spark, a coil could
be faulty. On four cylinder machines try
disconnecting one coil at a time, and
switching on and off, checking for
On other machines the coils are
used singularly or connected in a chain
in series. One
coil failing can stop sparking but if it
becomes short circuit to its case the
coils after it in the chain will stop
working. It is possible that a working
coil is shorting to case, and stopping
the other coils in the chain from
working. This is very common when a
Lucas coil is over tightened in the
metal clamp, the case becomes crushed
and touches the windings inside This can
occur when the coil warms up. The Micro-MKIII,
Micro- Digital and Micro-Power units all
turn off when not being triggered,
therefore it is best to carry out the
next test as you may not always have a
spark on turning on and off.
SPARKS ON SWITCHING ON & OFF but not on cranking. Disconnect the wires from the ignition box that go to the stator plate. With the ignition on, touch these two wires together ,making and breaking should produce a spark at the sparkplugs. If sparks are present then the ignition box is most likely to be in good order, if none are present the box is faulty. The only units that will not trigger in this way are the racing crank triggered Digital, and Norton rotary unit. Check that the rotor magnets are running within the two metal pole pieces. On British machines, if necessary the rotor can be moved out slightly by placing a thin metal shim around the taper. The ignition will not fire if turned by hand at less than 200 RPM.
STATOR PLATE. A full visual check of the condition of the
circuit board and coils looking for
loose or broken parts. Check for signs
of the rotor touching the solder
connections. Using a multimeter check
the resistance of each pickup coil and
then the total resistance across the
wires or terminal With the meter still
connected, run your fingers round the
coils, if the resistance changes there
could be a broken winding inside.
ROTOR.. The magnets should just hold the weight of the rotor
when placed against apiece of steel. Check
the marking spots are the same way
round. All magnets should have a similar
amount of strength.
SPARKS ON CRANKING BUT WON'T FIRE. Check the stator wires do not change colour in the wiring loom, as swapping these will make the ignition fire over 50 degrees retarded. With a digital system check you have suppressed plug caps fitted of approx. 5,000 ohms. lf timing has just been done, don't forget that the timing angle on the camshaft is half of the crankshafts (ie on a 650 Triumph full advance timing is 38 degrees crankshaft but is set at 19 degrees on the camshaft.}.
CONTINUOUS SPARKING WITHOUT CRANKING THE ENGINE. A poor battery with a battery charger connected or one or more bad cells in the battery. A high resistance in the wiring circuit or earth return. Check that the engine is earthed back to the frame and battery circuit. Plastic coated frames must have a good earth return to the engine case. A wrong type of ignition coil with a very low primary resistance, this will draw a very high current and produce a large volt drop across the wiring. The unit will keep turning on and off generating a chain of sparks.
ENGINE RUNS FAST AT IDLE ,KICKS BACK ON STARTING. Poor fuse connection or wiring running low or variable voltage to the ignition. As the alternator charges into the system with increasing speed the problem canclear.
ENGINE RUNS(POOR STARTING) BUT MISFIRES. Poor ignition switch or bad connection vibrating on and off. Spark plug caps open circuit (suppressors broken up).
Stainless Steel Braided Brake Hoses
I recently had a local company called Maltech make me some SS braided hoses for my XS650SG so I thought some of you may be interested in seeing the process. David Malkin turned up at my door equipped with all manner of fittings and proceeded to pull all the old rubber hoses off my bike and make up exact copies in braided stainless steel including the fittings.
These hoses are ADR approved and the machine that does the crimping is portable so the work can be done on site and can even pressured test the new hoses to some incredible pressure ( 3000 lbs per square inch I think was mentioned )
The work done and David was on his way but before he left I asked him if he could make these up via mail order he said he could. Maltech has a website at www.maltech.com.au and if you send him your old hoses and fittings (banjo bolts for thread type and size) to copy he will make up the new ones and post them back to you. The cost for me was $295 for the three front brake hoses and SS fittings. If you are interested in getting some done you can call David on 0418 378 939
Lastly, they work great.