Page 328 of 414
8-73
5. Screw in the adjusting bolt on the brake cali-
per by hand until it feels tight, then screw it
out 1/8 turn. Tighten the adjusting bolt locknut
to the specified torque.CAUTION:_ When tightening the locknut, hold the adjust-
ing bolt with a wrench so that the adjusting
bolt does not turn together with the locknut. _
WARNING
_ Operating with improperly adjusted brakes
could cause the brakes to malfunction, result-
ing in reduced braking performance. This
could increase the chance of a collision or ac-
cident. After adjusting the parking brake, block
the rear of the machine off the ground and spin
the rear wheels. Check to make sure there is
no brake drag. If brake drag is noticed, perform
the adjustment again. _
Tightening torque:
Locknut:
16 Nm (1.6 m·kgf)
U5LP61.book Page 73 Monday, August 27, 2001 3:49 PM
Page 336 of 414

8-81 1. Upper wheel hub nut 2. Lower wheel hub nut
1.Écrou supérieur de moyeu de roue
2.Écrou inférieur de moyeu de roue
1. Tuerca superior del cubo de la rueda
2. Tuerca inferior del cubo de la rueda
1. Locknut (× 2) 2. Adjusting bolt (× 2)
3. Alignment marks (× 2)
1. Contre-écrou (× 2) 2. Boulon de réglage (× 2)
3. Repères d’alignement (× 2)
1. Contratuerca (× 2) 2. Perno de ajuste (× 2)
3. Marcas de alineación (× 2)
EBU01026
Drive chain slack adjustment
1. Loosen the rear wheel hub upper and lower
nuts.
2. Loosen the adjusting bolt locknuts on each
side of the swingarm. To tighten the drive
chain, turn the adjusting bolts in direction
a.
To loosen the drive chain, turn the adjusting
bolts in direction
b and push the wheels for-
ward. Turn each adjusting bolt exactly the
same amount to maintain correct axle align-
ment.
There are alignment marks on each side of
the swingarm and on the hub. Use them to
check for proper wheel axle alignment.
3. After adjusting, tighten the adjusting bolt lock-
nuts and the wheel hub nuts to the specified
torques.
Tightening torques:
Locknut:
16 Nm (1.6 m·kgf)
Upper wheel hub nut:
90 Nm (9.0 m·kgf)
Lower wheel hub nut:
90 Nm (9.0 m·kgf)
U5LP61.book Page 81 Monday, August 27, 2001 3:49 PM
Page 350 of 414
8-95 1. Nut (× 4)
1.Écrou (× 4)
1. Tuerca (× 4)
Front
Avant
Delantera1. Nut (× 4)
1.Écrou (× 4)
1. Tuerca (× 4)Rear
Arrière
Trasera
EBU00373
Wheel removal
1. Elevate the wheel by placing a suitable stand
under the frame.
2. Remove the nuts from the wheel.
3. Remove the wheel assembly.
U5LP61.book Page 95 Monday, August 27, 2001 3:49 PM
Page 352 of 414
8-97 1. Arrow mark
1. Flèche
1. Flecha
Front
Avant
Delantera1.“SIDE FACING OUTWARDS”
1. Inscription “SIDE FACING OUTWARDS”
1.“SIDE FACING OUTWARDS”Rear
Arrière
Trasera
EBU00782
Wheel installation
When installing a wheel, reverse the removal pro-
cedure.NOTE:
When installing a front wheel, the arrow mark
on the tire must point toward the rotating
direction of the wheel.
When installing a rear wheel, the wording on
the tire “SIDE FACING OUTWARDS” must be
facing outwards.
Tighten the wheel nuts to the specified torque.
Wheel nut torque:
Front: 45 Nm (4.5 m·kgf)
Rear: 45 Nm (4.5 m·kgf)
U5LP61.book Page 97 Monday, August 27, 2001 3:49 PM
Page 382 of 414
9-1
EBU00418
CLEANING AND STORAGE
A. CLEANING
Frequent, thorough cleaning of your machine will
not only enhance its appearance but will improve
its general performance and extend the useful life
of many components.
1. Before cleaning the machine:
a. Block off the end of the exhaust pipe to pre-
vent water entry. A plastic bag and strong
rubber band may be used.
b. Make sure the spark plug and all filler caps
are properly installed.
2. If the engine case is excessively greasy, ap-
ply degreaser with a paint brush. Do not ap-
ply degreaser to the chain, sprockets or
wheel axles.
3. Rinse the dirt and degreaser off with a garden
hose. Use only enough pressure to do the
job.
U5LP61.book Page 1 Monday, August 27, 2001 3:49 PM
Page 384 of 414
9-3
CAUTION:
Excessive water pressure may cause water
seepage and deterioration of wheel bearings,
brakes, transmission seals and electrical de-
vices. Many expensive repair bills have result-
ed from improper high pressure detergent
applications such as those available in coin-
operated car washers.4. Once the majority of the dirt has been hosed
off, wash all surfaces with warm water and
mild, detergent-type soap. An old toothbrush
or bottle brush is handy for hard-to-get-at
places.
5. Rinse the machine off immediately with clean
water and dry all surfaces with a chamois,
clean towel or soft absorbent cloth.
6. Dry the chain and lubricate it to prevent rust.
7. Clean the seat with a vinyl upholstery cleaner
to keep the cover pliable and glossy.
U5LP61.book Page 3 Monday, August 27, 2001 3:49 PM
Page 390 of 414
9-9
5. Block up the frame to raise all wheels off the
ground.
6. Tie a plastic bag over the exhaust pipe outlet
to prevent moisture from entering.
7. If storing in a humid or salt-air atmosphere,
coat all exposed metal surfaces with a light
film of oil. Do not apply oil to any rubber parts
or the seat cover.
8. Remove the battery and charge it. Store it in
a dry place and recharge it once a month. Do
not store the battery in an excessively warm
or cold place (less than 0°C or more than
30°C).NOTE:Make any necessary repairs before storing the
machine.
U5LP61.book Page 9 Monday, August 27, 2001 3:49 PM
Page 392 of 414
10-1
EBU00428
SPECIFICATIONS
MODEL YFM660R
Dimension:
Overall length
Overall width
Overall height
Seat height
Wheel base
Ground clearance
Minimum turning radius1,830 mm
1,100 mm
1,150 mm
860 mm
1,245 mm
265 mm
3,300 mm
Basic weight:
With oil and full fuel tank 193 kg
Engine:
Type
Cylinder arrangement
Displacement
Bore
× stroke
Compression ratio
Starting system
Lubrication systemLiquid-cooled, 4-stroke, SOHC
Forward inclined single cylinder
660 cm
3
100
× 84 mm
9.2 : 1
Electric starter
Dry sump
U5LP61.book Page 1 Monday, August 27, 2001 3:49 PM