FUEL AND EXHAUST SYSTEMS
5. If the backfiring is different, the vacuum
switch is faulty. Install a new switch.
Do not scrape deposits off or the
assembly will be damaged.
9. Install by reversing the removal steps.
Vacuum Switch Test
Inspect the vacuum switch if there is
backfiring during deceleration o r other
abnormal engine noise.
1. Run the engine until it is warm.
2. Rev the engine to 4,000 rpm and snap the
throttle shut. Note the intensity and frequency
of any backfiring for comparison later in this
3. Shut the engine off and, at the air cleaner
housing. disconnect and plug the hose from the
vacuum switch (Figure 40).
4. Start the engine, rev it to 4,000 rpm, snap
the throttle shut and compare the backfiring to
what you heard before. If the backfiring is the
same, there is nothing wrong with the vacuum
As water and dirt accumulate in the fuel
tank, engine performance will deteriorate. The
fuel system should be cleaned when the engine
S o m e fuel m a y spill during these
procedures. Work in a well-ventilated
area at least 50 feet from any sparks or
jlames, including gas appliance pilot
lights. Do not smoke in the area. Keep a
BC ratedfire extinguisher handy.
1. Check that the ignition switch is OFF.
2. Put the bike up on its centerstand.
3. Swing the seat open or remove it.
4. Turn the fuel tap ON and disconnect the
fuel and vacuum lines at the fuel tap. Lift up the
rear of the tank slightly,
5. On models with fuel level gauges or warning
lights, disconnect the fuel level sensor wires.
6. Pull the tank up and to the rear and remove
7. Discard the fuel in the tank. Pour about a
pint of clean fuel into the tank, install the cap,
slosh the fuel around for about a minute and
pour it out into a safe container.
8. To install, reverse the removal steps. Note
a, Insert the tank brackets carefully over the
frame grommets (Figure 41). Don't pinch
any wires or control cables.
Property of www.SmallEngineDiscount.com - Not for Resale