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WHAT’S WRONG WITH A
SIMPLE ON - OFF TAP ?
There’s nothing whatsoever
wrong with an on - off design. It’s people like you and I that are
the weak link. we tend to forget to turn them off. The consequences of
which can be disastrous.
Once fuel is delivered to the carbs they have to regulate its delivery
into the engine, and can only hold so much in their float bowls. Once
the float bowls become full, their fuel shut off valves stop the fuel
delivery from the tap. That is providing that everything is set correctly.
However, if they fail to shut off the fuel and the fuel tap (and gravity)
is still delivering fuel, the petrol has only two places to go. Forward
or backwards.
If it goes backwards into the airbox it will quickly find its way down
into the sump via the crankcase breather, and contaminate your engine
oil. If it goes forward it may fill up a cylinder with fuel.
Then, the next time you try and start the engine, the piston will come
up on its compression stroke expecting to find a nice fuel / air mixture
to ignite, and instead will find a cup full of petrol. Having been thrown
round at speed and being unable to compress or expel the fuel, it's likely
to bend conrods and things! Mr Kawasaki fitted a vacuum operated tap in
order to protect you from yourself. Never be tempted to fit after market,
in-line fuel filters they restrict fuel flow too much, and lead to all
sorts of running problems.
Never leave the fuel tap
in the Prime position.(Or use an on - off tap.)
WHAT GOES WRONG, AND HOW
DO I FIX IT ?
A number of complaints are
common to this type of fuel tap, and all of them must be rectified at
the earliest opportunity, to ensure reliability, and avoid internal engine
damage. All faults will manifest themselves by either poor running / cutting
out, or by the tap delivering fuel when it shouldn’t.
FUEL IS LEAKING, FROM THE
TAP
Fuel dripping onto engine casings
from the tap is due to an O ring or gasket failure.
FUEL COMES OUT OF THE TAP
WHEN THE ENGINE IS NOT RUNNING.
Check that the tap is not on
PRI. If the tap is on RUN or RES, and fuel is issued, it is almost certainly
due to a stretched, or perforated diaphragm (I). Or, the blowback valve
has seized, and is “holding” a vacuum between it, and the diaphragm.
Replace the diaphragm (I), and return spring (J), and if this fails to
rectify the complaint, investigate the blowback valve. It often gets a
corrosion build up, and will benefit from a clean out,and a squirt of
WD 40. You may wish to consider discarding it, but this is not an endorsement,
be aware of its role. Try slitting it from edge to centre, this will help
the pressure equalise without detracting from its function too much.
THE ENGINE FADES WHEN IN
THE CRUISE.
“Sudden death syndrome.”
normally strikes when your sitting at a steady 60 - 80 mph. Quite simply
the carbs run dry, and the engine is starved of fuel. If you’re quick,
you can spin the tap round to PRI, just as you would when switching from
RUN to RES when running low. This should deliver fuel quickly enough for
the engine to pick up, and get you home. If you do end up at the side
of the road, turn it to PRI wait 10 seconds, and the machine should start.
If it doesn’t and your convinced its fuel starvation, try opening
the fuel filler cap. It may be that the fuel tank is not venting correctly,
and is creating its own vacuum. This will oppose, and work against the
vacuum provided by the engine, eventually becoming strong enough to pull
the diaphragm shut.
Once you’re up and running again try to turn the tap round to RUN,
it may well continue to function normally with no further problems. Check
also the quality, and integrity of the connections of the vacuum pipe
feeding the tap. If in doubt overhaul the tap.
CONCLUSION.
If its not broken don’t
fix it. Be aware of how the fuel tap operates, and learn to identify it’s
shortcomings. Avoid aftermarket overhaul kits, (Tourmax) they are rarely
effective, only use genuine Kawasaki parts.
Ring 01380 860641.
Meridian,The
GPZ Zone www.gpz900r.co.uk
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