Honda CB900F Service Manual page 428

TROUBLESHOOTING
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11. Check for engi ne ov er heat ing - - - - - -- Ove rheating
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N ot ove r heati ng
Possible cause
Coolant lev el lo w
Fan motor not wo rking (fau lty fan
m ot or swi t ch )
T her m o st at st uck clo sed
Excessive carbon build -u p in
co m b ust io n chamber
Use of poor q uali ty fuel
W ro ng ty pe of f uel
Clutch slipping
12. A ccel erate or run at hi gh speed - - - - - -- Eng ine kno cks - -- - -.
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E n gine does n ot knock
Wo rn pist o n an d cylinde r
Wrong t yp e of f ue l
Excessi v e ca r bon bu ild-u p in co m-
bustion c ham ber
Ignition timing to a dv a nce d (fa ulty
ECM )
Lean fue l m ixture
POOR PERFORMANCE AT LOW AND IDLE SPEED
Possible caus e
1. Check ig ni tio n tim in g - - -- - -- - - - - Inco r rect - - - -- - -...
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• Improper ign it ion tim in g
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Cor rect
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2. Check t he starter v alv e syn chroni zation - - - - Inco rre ct
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Corr ect
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See secti o n 5
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Fau lty spark p lug
Fau lty carb on or w et fo u led sp ark
plug
Faulty ECM
Fau lty ign it ion coil
Faul ty en gin e stop sw itc h
Faulty ig ni ti on pu lse ge nerato r
Faul t y ignition switch
Lo ose or disconn ected ignition
sys te m wi res
- -- - - - - - - - Abno rmal
- - - - -- - t ..
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See section 5
Good spark
3. Insp ect t he fu el fl ow - -- - - -- - - -- A b no rm al
- - - -- - - t ...
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Fau lt y pr essure regul at or (Section 5)
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Norma l
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4. Inspect th e f ue l inj ect or
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Norm al
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5. Check for leak s in the inta ke pipe - - - - - - Leaking - -- - -- - __ ..
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Loose in sul ator cla mp
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Damaged insu lat o r
Not leaking
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6. Perform spark test - - - - - - - - - - - - Weak or interm ittent
j
spark
21-3