Use the
DYN
mode to check for and analyse defective engine seals in case of apparent difficulty in
arriving at a satisfactory synchronisation, even after several attempts and probably associated with an
irregular engine rhythm. The function of the
DYN
mode is to compare the waveform heights of each
connected channel (cylinder) and the relative positions of their crests & troughs, which should be
similar for each channel. The precise values themselves are not relevant to this purpose. For more
details on using the “DYN” mode, refer to page 7, section §
8.
DIAGNOSTICS.
4. ENGINE SPEED, RPM (Revolutions Per Minute).
In RPM mode the
VacuumMate
monitors the waveform pulses from the pneumatic engine
connections, so no other pick-up or probe is required. As the waveform pulses are not subject to
interference or other HT parasitic stray signals they provide a much easier and more reliable signal
input than other methods.
The RPM function receives it’s signal input from the waveform pulses from
the #1 channel hose connection, so it is important to connect this hose in cases where not all four hose
connections are made.
The RPM function is selected by the RPM/VAC selector switch (#8, illustration, inside front cover).
For many Japanese motorcycles and some other engines, adjustment of the engine speed to within
about 50 RPM of the correct value (as stipulated by the constructor) is essential for precise intake
synchronisation. Vehicle tachometers are usually imprecise at low-end engine speeds and should not
be used for setting or monitoring engine speed for synchronising purposes. This is therefore a vital
feature of the VacuumMate.
The engine speed should be re-adjusted accurately to the correct idling
speed on completion of the synchronising task.
The
RPM
mode displays engine speeds from 500 to 2500 rpm, with 50 rpm resolution. The 2-stroke /
4-stroke selector switch (#11, illustration, inside front cover) allows correctly displayed values for both
types of engine. Incorrect selection will display either double the true RPM (4-stroke selected for 2-
stroke) or half of it (2-stroke selected for 4-stroke).
5. POWERING THE VACUUMMATE
The
VacuumMate
(standard model, ref
VMR6WS
)
requires a 12Vdc external power source such as a
charged 12V battery with a capacity of at least 4Ah. To connect to this, a cord-set with alligator clips is
included in the VacuumMate kit. (Replace this immediately in case of damage or wear, see §
9.
SERVICE)
. Alternatively, use a well-regulated DC power supply with a power rating of at least 20W
and delivering between 11Vdc & 15Vdc.
NOTE
: Use only a DC power supply which you have
ensured is correctly rectified, filtered and regulated. To do otherwise may damage the VacuumMate
circuitry & invalidate the warranty. If using a 12 Volt vehicle battery make sure it is in good condition. A
battery in poor condition or a bad connection can give rise to unstable power conditions such as
voltage spikes that may damage the VacuumMate.
The
VMR6ME
model has internal rechargeable 7,2V NiMH batteries. These can be recharged when
necessary by connecting an external well charged 12V battery or regulated 12Vdc power supply using
the connection cable set supplied. The external source can also be used to power the VMR6ME, but
NOT, for safety reasons, when used on boats. On shore, whenever an external battery or 12Vdc
power source is to be connected to power the VMR6ME or for recharging the internal batteries, place
the battery selection switch in the 12V position before connecting and leave it so until the task or
recharging is completed, then disconnect.
BATTERY SELECTION
External
12V
Internal NiMH
LOW
BATTERY
VMR6ME
LED
3
