Page 236 of 362

8-7
EBU02621
PERIODIC MAINTENANCE/LUBRICATION
NOTE:8For ATVs not equipped with an odometer or an hour meter, follow the month maintenance intervals.
8For ATVs equipped with an odometer or an hour meter, follow the km (mi) or hours maintenance intervals. However, keep in mind
that if the ATV isn’t used for a long period of time, the month maintenance intervals should be followed.
INITIAL EVERY
month 1 3 6 6 12
ITEM ROUTINEWhichever
km 320 1200 2400 2400 4800 comes first
(mi) (200) (750) (1500) (1500) (3000)
hours 20 75 150 150 300
Valves*• Check valve clearance.
1111
• Adjust if necessary.
• Check condition.
Spark plug• Adjust gap and clean.11111
• Replace if necessary.
Air filter element
• Clean. Every 20–40 hours
(for engine and V-belt
• Replace if necessary. (more often in wet or dusty areas)
case)
Carburetor*• Check idle speed/starter operation.
111 1
• Adjust if necessary.
Cylinder head cover• Check breather hose for cracks or damage.
111
breather system*• Replace if necessary.
• Check leakage.
Exhaust system*• Retighten if necessary.111
• Replace gasket if necessary.
Fuel line*• Check fuel hose for cracks or damage.
111
• Replace if necessary.
Engine oil• Replace (warm engine before draining).1111
1C5-9-61-08 9/4/04 9:30 AM Page 8-8
Page 328 of 362

8-99
EBU00440
Troubleshooting chart
1. Fuel
Check if there is
fuel in the fuel
tank.
2. Compression
Use electric starter
to see if there is
compression.
3. Ignition
Remove plug and
check electrodes.
WetWipe clean with dry
cloth.
DryAttach plug cap and
ground to chassis.Use electric
starter.Spark weak.
Spark good.Ignition system normal.
No spark.
Ask a Yamaha dealer to inspect.
Adjust plug gap or
replace plug.
There is compresson.Compression normal.
Ask a Yamaha dealer to inspect.No compression.
There is fuel.Turn the fuel
cock to “OFF”.
Remove the
fuel hose from
the fuel cock.
Some fuel.Turn the fuel
cock to “RES”.Restart engine.
No fuel.Supply fuel.
4. Battery
Use electric
starter.
Engine turns
over quickly.Battery good.
Engine turns
over slowly.Check fluid, recharge,
check connections.
Check fuel flow.
Water or dirt
mixed in fuel.
Turn the fuel
cock to “ON”.No fuel.Fuel cock clogged.
Clean the fuel filter
and the fuel tank.
Clean fuel cock.
1C5-9-61-08 9/4/04 9:30 AM Page 8-100
Page 344 of 362
10-3
Model YFM125G
Air filter:
for engine Wet type element
for V-belt compartment Dry type element
Fuel:
Type Unleaded gasoline only
For Europe:Regular unleaded gasoline only with a
research octane number of 91 or higher
Fuel tank capacity 7.6 L
Fuel reserve amount 1.3 L
Carburetor:
Type/manufacturer VM18SH/MIKUNI
Spark plug:
Type/manufacturer CR7HS/NGK
Gap 0.6–0.7 mm
Clutch type: Dry, centrifugal automatic
Transmission:
Primary reduction system Helical gear/Spur gear
Primary reduction ratio 43/14 ×40/17 (7.226)
Secondary reduction system Chain drive
Secondary reduction ratio 32/12 (2.666)
Transmission type V-belt automatic
Operation Centrifugal automatic type
Reverse 49/14 ×49/15 ×40/17 (26.902)
1C5-9-61-09~11 9/4/04 9:29 AM Page 14