Honda Hawk GT NT650 1988 Service Manual page 251

TROUBLESHOOTING
POOR ENGINE PERFOMANCE AT HIGH SPEEDS
NOTE
Check the engine oil level and condition. Be sure the oil is not contaminated by coolant or metal burrs.
Start the engine and warm it up to operating temperature, then check to see if the temperature gauge indicates the normal
range. If the gauge reading is abnormal, refer to sections 5, 18.
Check the idle speed: specified 1,200
±
100 rpm.
Check that the wheels spin freely: Also, see sections 12, 13, 14.
POSSIBLE CAUSE
1.
Check spark plug condition
I
NORMAL
2.
Check exhaust smoke at half-throttle
I
NO PROBLEM
3.
ChL
'"0'"'
,,,,.,m,",,
wtth
choke applied
I
DOES NOT IMPROVE
C
!. .
4. heck engine performance without
air cleaner element
I
DOES NOT IMPROVE
5. Tes\ the specified fuel flow
I
NO PROBLEM
6 T t l ' . .
. est cy Inder compression uSing
compression gauge
I
COMPRESSION NORMAL
7 Ch
!
k' .. . . . . .
. ec Ignition timing uSing timing
light with full-advanced
I
NORMAL
Icottinued on following page)
20-6
WET PLUG - - - - - - - - - - - . . . . . . Rich mixture
Dirty air cleaner element
Improper heat range
DISCOLOURED---------- .. • Improper heat range
(Light gray, White) Lean mixture
Improper float level
Intake pipe leaking
BLUE - - - - - - - - - - - - -......
~.
Engine oil leaking; refer to sections
9, 10
G R A Y - - - - - - - - - - - - -..... • Rich mixture
• Worn piston rings
BETTER CONDITION - - - - - - -...... ~. Lean mixture
Intake pipe leaking
Improper carburetor adjustment
Clogged jets
Improper float level
BETTER CONDITION-------...,...... • Dirty air cleaner element
Rich mixture
Clogged carburetor air passages
Improper float level
UNDER THE SPECIFIED------ .. • Dirty fuel filter
Clogged fuel lines
Faulty fuel pump or pump relay
LOW COMPRESSION
--------1...
~.
Improper valve and seat contact
Valve stuck open
Damaged cylinder head gasket
Worn cylinder and piston rings
ABNORMAL----------_ .. • Improper ignition timing
(Faulty pulse rotor or generator with
ferrous burrs)