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Problem: Engine noisy (Noise seems to come from transmission)
Condition
Remedy
1.
Gears
worn - chipped
2.
Splines
worn
3.
Primary gears
worn - chipped
4.
Bearings
worn
5.
Bushing
worn
1. Replace gears
2. Replace shaft(s)
3. Replace gears
4. Replace bearings
5. Replace bushing
Problem: Engine noisy (Noise seems to come from secondary bevel gear and final driven shaft)
Condition
Remedy
1.
Drive - driven bevel gears
damaged - worn
2.
Backlash
excessive
3.
Tooth contact
improper
4.
Bearing
damaged
5.
Gears
worn - chipped
6.
Splines
worn
1. Replace gears
2. Adjust backlash
3. Adjust contact
4. Replace bearing
5. Replace gears
6. Replace shaft(s)
Problem: Engine idles poorly
Condition
Remedy
1.
Valve clearance
out of adjustment
2.
Valve seating
poor
3.
Valve guides
defective
4.
Rocker arms - arm shaft
worn
5.
Magneto
defective
6.
CDI unit
defective
7.
Spark plug
fouled - gap too wide
8.
Ignition coil
defective
9.
Float
out of adjustment
10.
Jets
obstructed
11.
Pilot screw setting
improper
1. Adjust clearance
2. Replace - service seats - valves
3. Replace cylinder head
4. Replace arms - shafts
5. Replace stator coil
6. Replace CDI unit
7. Adjust gap - replace plug
8. Replace ignition coil
9. Adjust float height
10. Clean jets
11. Adjust pilot screw
Problem: Engine runs poorly at high speed
Condition
Remedy
1.
High RPM “cut out”
against RPM limiter
2.
Valve springs
weak
3.
Valve timing
incorrect
4.
Cam - rocker arms - tappets
worn
5.
Spark plug gap
too narrow
6.
Ignition coil
defective
7.
Float level
too low
8.
Air cleaner element
obstructed
9.
Fuel hose
obstructed
1. Shift into higher gear - decrease speed
2. Replace springs
3. Correct timing - check chain, sprockets, and cam chain ten-
sioner
4. Replace cam - arms - tappets
5. Adjust gap
6. Replace ignition coil
7. Adjust float height
8. Clean element
9. Clean or replace hose
Problem: Exhaust smoke dirty or heavy
Condition
Remedy
1.
Oil (in the engine)
overfilled - contaminated
2.
Piston rings - cylinder
worn
3.
Valve guides
worn
4.
Cylinder wall
scored - scuffed
5.
Valve stems
worn
6.
Stem seals
defective
1. Drain excess oil - replace oil
2. Replace - service rings - cylinder
3. Replace cylinder head
4. Replace - service cylinder
5. Replace valves
6. Replace seals
Problem: Engine lacks power
Condition
Remedy
1.
Valve clearance
incorrect
2.
Valve springs
weak
3.
Valve timing
incorrect
4.
Piston ring(s) - cylinder
worn
5.
Valve seating
poor
6.
Spark plug
fouled
7.
Rocker arms - shafts
worn
8.
Spark plug gap
incorrect
9.
Air cleaner element
obstructed
10.
Oil (in the engine)
overfilled - contaminated
11.
Intake manifold
leaking air
12.
Cam chain
worn
13.
Carburetor jets
obstructed
14.
Float level
out of adjustment
1. Adjust clearance
2. Replace springs
3. Re-time valve gear
4. Replace - service rings - cylinder
5. Replace cylinder head/valves
6. Clean - replace plug
7. Replace arms - shafts
8. Adjust gap - replace plug
9. Clean element
10. Drain excess oil - change oil
11. Tighten - replace manifold
12. Replace cam chain
13. Clean jets
14. Adjust float height
