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SSeeccttiioonn 77
DDIIAAGGNNOOSSTTIICC TTEESSTTSS
measured. During cranking and running this read-
ing should go to “Infinity”. Verify that the meter
leads were properly connected as per Step 2
instructions.
2. If battery voltage was not measured in Step 3, reconnect Wire
15 and Wire 14 to their correct terminal locations.
Figure 7-40. – Engine Ground Harness Test Points
3. If “Infinity” was not measured in Step 15, repair or replace
grounded Wire 18A between the J1 Connector and the insulat-
ed terminal stud or defective insulated terminal stud.
4. If sparking still does not occur after adjusting the armature air
gap, testing the ground wires and performing the basic flywheel
test, replace the ignition magneto(s).
Note: Before replacing the Ignition Magneto,
check the Flywheel Magnet.
CHECKING FLYWHEEL MAGNET:
The flywheel magnet rarely loses its magnetism. If
you suspect a magnet might be defective, a rough
test can be performed as follows:
1. Place the flywheel on a wooden surface.
2. Hold a screwdriver at the extreme end of its handle and with its
point down.
3. Move the tip of the screwdriver to about 3/4 inch (19mm) from
the magnet. The screwdriver blade should be pulled in against
the magnet.
FLYWHEEL KEY:
In all cases, the flywheel taper is locked on the crank-
shaft taper by the torque of the flywheel nut. A key-
way is provided for alignment only and theoretically
carries no load.
If the flywheel key becomes sheared or even partially
sheared, ignition timing can change. Incorrect timing
can result in hard starting or failure to start.
Remove and inspect flywheel key for damage.
TEST 35 - CHECK VALVE ADJUSTMENT
DISCUSSION:
The valve lash must be adjusted correctly in order to pro-
vide the proper air/fuel mixture to the combustion chamber.
ADJUSTING VALVE CLEARANCE:
Adjust valve clearance with the engine at room tem-
perature. The piston should be at top dead center
(TDC) of its compression stroke (both valves closed).
An alternative method is to turn the engine over and
position the intake valve fully open (intake valve
spring compressed) and adjust the exhaust valve
clearance. Turn the engine over and position the
exhaust valve fully open (exhaust valve spring com-
pressed) and adjust the intake valve clearance.
Correct valve clearance is given below, in INCHES
(MILLIMETERS).
IInnttaakkee VVaallvvee 00..000022--00..000044 ((00..0055--00..11))
EExxhhaauusstt VVaallvvee 00..000022--00..000044 ((00..0055--00..11))
1. Loosen the rocker arm jam nut. Use a 10mm allen wrench to turn
the pivot ball stud while checking the clearance between the
rocker arm and valve stem with a feeler gauge (see Figure 7-41).
Figure 7-41 – Adjusting Valve Clearance
2. When clearance is correct, hold the pivot ball stud with the
allen wrench and tighten the rocker arm jam nut to the speci-
fied torque with a crow's foot. After tightening the jam nut,
recheck valve clearance to make sure it did not change.
TORQUE SPECIFICATION
ROCKER ARM JAM NUT
174 inch-pounds
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