Engine Lacks Power - Honda Nighthawk CB 750 1991 Service Manual

Troubleshooting
Engine Lacks Power
Possible Cause
1. Raise wheels off ground and spin -Wheels Do Not Spin Freely
*.
Brake dragging
by hand
-
Worn or damaged wheel bearings
I
Wheel bearings need lubrication
Wheel Spins Freely
-
Drive chain too tight
1 : .
2. Check tlre pressure Pressure Low
--
Faulty tire valve
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~re$sure Normal
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3.
Accelerate rapidly from low to
-
Engine Speed Not Changed When-. Clutch slipping
second Clutch is Released
-
Worn clutch discstplates
1
Warped clutch discstplates
Engine Speed Lowered When
-
Weak clutch spring
Clutch is Released
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4. Accelerate lightly
Engine Speed Does Not Increase-. Carburetor choke closed
1
-
Clogged air cleaner
Engine Speed Increases Restricted fuel flow
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-
Clogged muffler
Pinched fuel tank breather
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5. Check ignition timing
Incorrect
-.
Faulty ignition control module
1
Faulty ignition pulse generator
Correct
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6. Check hydraulic tappet conditions -Incorrect
*
Clogged tappet oil holes
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-
Worn valve seat
Correct
-
Damaged tappaet
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7. Test cylinder compression Too Low
*.
Valve stuck open
1
Worn cylinder and piston rings
NOri"'
-
Leaking head gasket
Improper vlave timing
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8. Check carburetor for clogging- Clogged
-.
Caburetor not sewiced frequently
I
1
enough
Not Clogged
4
9. Remove spark plug Fouled or Di s col o red-. Plugs not serviced frequently
1
enough
Not Fouled or Discolored
Spark plugs are incorrect heat range
I I
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10. Check oil level and condition Incorrect *- Oil level too high
-
Oil level too low
Correct Contaminated oil
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11. Remove cyl~nder head cover and- Valve Train Not Lubricated *- Clogged oil passage
inspect lubrication Properly
-
Clogged oil control orifice
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Valve Train Lubricated
Properly
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