Solving Air/Petrol System Problems - MINSK Repair Manual

Finally, if your kick stand is weak causing your bike to lean over to its left at
an acute angle then the mechanics of the float in the carburettor can be inhibited.
The float can get jammed before it closes off the petrol which means that it will
always flood.
Solving Air/Petrol System Problems
First kick-start the engine a few times with the start/stop switch off and then
with it on. Then try the same process but with the choke on. Then remove the
sparkplug and have a look at it. It will either be dry, wet from water or wet from
too much petrol.
If the sparkplug is dry then first check that petrol can flow into the carburettor.
Pull out the petrol tube coming down from the tank. Check that the rubber seal
between the air-box and carburettor is fitted snugly and that the air-filter is tightly
screwed on. Otherwise too much air can get into the system and make the
petrol/air mix 'dry'. Then screw the sparkplug back onto the engine and kick-start
the engine many times with the key off and the choke on. Then try and start it with
the key on and the choke either on or off. Repeat a few times. Then put a little
petrol on the sparkplug, re-screw it back onto the engine and kick-start the bike.
This often does the trick.
If you still can not start the bike and the sparkplug doesn't smell of petrol then
remove the carburettor and clean out the jets. There is a more detailed description
of how to do this in the next section. Make sure the float tank's movement is not
hindered and the petrol stopping pin is not jammed due to poor workmanship or a
dirty, sticky washer. While you're at it, check that the two gasket seals between
the engine and carburettor are tight and good.
If the sparkplug is too wet instead of being dry then you first need to determine
if the wetness is from water or petrol. Water tends to make the sparkplug stay
wetter for longer, leaves a slightly white, grey film on the end, and smells like
nothing. If you think that's your problem then check to see if there is water in the
air box. There is dribble hole at the bottom of the box. Make sure that it is open
and the water can get out. Then empty out and clean the petrol filter as this is
where water collects from the tank. Also remove any residue in the filter as it may
eventually find its way into the jets in the carburettor. Then remove the carburettor
and empty out the water contaminated petrol. When mixed into petrol, water sinks
to the bottom, looks like melted wax and binds together in balls. It goes without
say that water might be a problem after rain or washing, but also know that this
problem can occur when the air is very moist and humid.
If you suspect that the sparkplug is wet because of too much petrol then open
the accelerator throttle for about 30 seconds. This will open up a gate in the
carburettor and air will be allowed to get in and help dry out the sparkplug. Then
try starting the bike without turning the accelerator handle. Then try turning the air
screw on the carburettor anti-clockwise as this will increase the proportion of air in
©Digby Greenhalgh 2000
Minsk Repair Manual
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