air source and look for any bubbles that would indicate leakage
from the tester.
6. Following the manufacturer's instructions, perform a cyl-
inder leakage test on the front cylinder. Make a note of
the percent of leakage. Leakage greater than 10% indic-
ates internal engine problems.
7. Listen for air leaks at throttle body intake, exhaust pipe,
and head gasket. Air escaping through the throttle body
indicates a leaking intake valve. Air escaping through the
exhaust pipe indicates a leaking exhaust valve.
NOTE
If air is escaping through valves, check for correct push rod
length.
8. Repeat procedure on rear cylinder.
NOTE
After installing spark plugs, be sure that throttle plate is in the
closed position before starting the engine.
DIAGNOSING SMOKING ENGINE OR HIGH
OIL CONSUMPTION
Perform both a compression test and a cylinder leakage test.
See 3.7 TROUBLESHOOTING, Compression Test and
3.7 TROUBLESHOOTING, Cylinder Leakdown Test. If further
testing is needed, remove suspect head(s) and inspect for the
following:
Check Prior To Cylinder Head Removal
1. Oil tank overfilled.
2. Oil carryover.
3. Breather hose restricted.
4. Restricted oil filter.
Check After Cylinder Head Removal
1. Oil return passages for clogging.
2. Valve guide seals.
3. Valve guide to valve stem clearance.
4. Gasket surface of both head and cylinder.
5. Cylinder head casting's porosity allowing oil to drain into
combustion chamber.
6. O-ring damaged or missing from oil pump/crankcase
junction.
2008 Dyna Service: Engine 3-15
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