KYMCO Grand Dink 250 Service Manual page 20

1
. GENERAL INFORMATION
ENGINE LACKS POWER
Inspection/Adjustment
Start engine and accelerate
lightly for observation
Check ignition timing
(using a timing light)
Check valve clearance
Test cylinder compression
Check carburetor for
clogging
Remove spark plug and
inspect
Remove oil dipstick and
check oil level and condition
Remove cylinder head oil
pipe bolt and inspect
Check if engine overheats
Rapidly accelerate or run
at high speed
Symptom
Engine speed
increases
Correct timing
Correct
Normal
compression
Not Clogged
Plug not fouled or
discolored
Correct and not
contaminated
Valve train lubricated
properly
Engine does not
overheats
Engine does not knock
Engine speed does
not increase
sufficiently
Incorrect timing
Incorrect
Abnormal
compression
Clogged
Plug fouled or
discolored
Incorrect or
contaminated
Valve train not
lubricated properly
Engine overheats
Engine knocks
GRAND DINK 250
Probable Cause
ÅClogged air cleaner
ÇRestricted fuel flow
ÉClogged fuel line between fuel
tank and carburetor
ÑClogged exhaust muffler
ÖFaulty auto bystarter
ÜSplit carburetor vacuum piston
diaphragm
ÅFaulty CDI unit
ÇFaulty A.C. generator
ÅImproper valve clearance
adjustment
ÇWorn valve seat (valve stem too
protruding
ÅImproper valve and seat contact
ÇWorn cylinder and piston rings
ÉBlown cylinder head gasket
ÑFlaws in cylinder head
ÖImproper valve timing
ÅClogged carburetor jets
ÅFouled spark plug
ÇIncorrect heat range plug
ÅOil level too high
ÇOil level too low
ÉOil not changed
ÅClogged oil pipe
ÇFaulty oil pump
ÅInsufficient coolant
ÇFaulty thermostat
ÉWorn cylinder and piston rings
ÑMixture too lean
ÖPoor quality fuel
ÜExcessive carbon buildup in
combustion chamber
áIgnition timing too early
àAir in cooling system
ÅExcessive carbon build-up in
combustion chamber
ÇPoor quality fuel
ÉClutch slipping
ÑMixture too lean
Ö Ignition timing too early
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