MINSK Repair Manual page 8

axis of the cam disk to the magnet in the generator. One revolution of the piston
causes one revolution of the cam disk and one revolution of the magnet.
The coils in the generator are positioned to release the charge at just the
moment when the piston begins to move down the cylinder again. In this way all
the explosive energy is converted into a downward push to the piston. This is
called the "timing of the generator". When a bike has bad timing then much of the
power is wasted because the moving parts work against each other. The timing can
be adjusted because the housing to which the coils are screwed to can be moved a
little to either side.
There are two types of generators made for use in the Minsk. In version #1 a
large solid magnet attached to the shaft inside the engine spins inside a set of six
coils which are on the inside of a fixed circular casing. Four of these coils make
electricity for the lights and horn while the remaining two make the bulk of the
charge for the sparkplug. On the outside of this fixed circular casing is an
additional coil called the transducer coil which boosts and lengthens the charge for
the sparkplug. In version #2 a number of smaller magnets fixed to the inside of the
movable circular casing connected to the shaft inside the engine spin around the
outside of a fixed set of six smaller coils. Of these six coils, four make the charge
for the lights and horn, one makes the bulk of the charge for the sparkplug while
the remaining smaller one is the transducer coil.
The coils which make the electricity for the light and horn are made of thick
strong wires and very, very rarely burn out. The two or three remaining coils
which make the charge for the sparkplug are made of thinner wire. They are more
likely to burn out and if they do then the bike will not start. Luckily they can be
casing
charge to
sparkplug
charge to
lights and
horn
timing
adjustment
replaced with Vietnamese copies. However, the original Russian coils are much
stronger than the Vietnamese replacements. The problem is that the Russian coils
are only sold when you buy a complete generator – you can not buy them as a
spare. Once they burn out you have to replace them with the much weaker
Vietnamese coils. The Vietnamese coils will last a while but you can never be
©Digby Greenhalgh 2000
Minsk Repair Manual
5
magnet (attached
to engine shaft)
Version #1
Outside
earth
transducer
coil
6 coils on
inside of
casing