LEHR BV025HH Operator's Manual page 15

MAINTENANCE
ROCKER ARM CLEARANCE ADJUSTMENT
This requires partial disassembly of the engine.
If you feel unsure or unquali ed to perform this,
take the unit to an authorized service center.
NOTE: Inspect the valve to rocker arm clearance
with a feeler gage after the rst 25 hours of
operation. The engine must be cold when checking
or adjusting the valve clearances. This task should
be performed in a clean dust free environment.
1. Remove the ve screws on the engine cover
with a phillips head screw driver (Fig. 22).
2. Remove the engine cover.
3. Disconnect the spark plug wire.
4. Clean dirt from around the spark plug. Remove
the spark plug by using a 16mm socket, turn CCW.
Engine Cover
Remove Five
Screws
Fig. 22
5. Clean dirt from around the rocker arm cover.
6. Remove the three screws holding the rocker
arm cover with a phillips head screwdriver.
7. Remove the rocker arm cover and gasket (Fig. 23).
Spark Plug
Rocker Arm Cover
Remove Three Screws
Fig. 23
8. Pull the starter rope slowly to bring the piston
9. Slide a feeler gage between the rocker arm and
Adjusting Screws
Jam Nuts
10. Check the spark plug and reinstall. Refer to
11. Reinstall the spark plug wire.
IF THE CLEARANCE IS NOT WITHIN SPECIFICATION
1. Loosen the jam nut and turn the adjusting screw
2. Tighten the jam nut when the clearance is set.
3. Recheck the both clearances. Readjust if
Spark Plug Wire
4. Reinstall the rocker arm cover using a new
5. Tighten cover screws evenly until snug.
6. Reinstall the engine cover checking the
• The recommended clearance for both intake and
• Use a standard automotive 0.005in (0.127mm) feeler
LEHR
to the top of its travel, (This position is known as
top dead center). Check that the piston is at the
top of its travel by looking down into the spark
plug hole. Both valves should be closed and the
rocker arms should move freely. If this statement
is not true, repeat this step.
the valve return spring. Measure the distance
between the rocker arm and valve stem (Fig. 24).
Take care to only measure the free play. It is very
easy to insert too thick a feeler gauge and
accidentally depress the valve and spring.
Measure both the intake and exhaust valve
clearances.
Rocker Arms
Fig. 24
Replacing the Spark Plug (p.14) .
as necessary. To increase the clearance, turn the
adjusting screw CCW. To decrease the clearance,
turn the adjusting screw CW.
necessary.
gasket.
alignment of the cover. Tighten the ve engine
cover screws until snug.
exhaust is 0.003-0.006in (0.076-0.152mm).
gage.
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Feeler Gauge
Exhaust Valve
Intake Valve
15