Yamaha YFM660 01 User Manual

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SPEC
Transmission:
Main axle deflection limit ---- 0.08 mm 
(0.0031 in)
Drive axle deflection limit ---- 0.08 mm 
(0.0031 in)
Shifter:
Shifter type Shift drum and guide bar ----
Decompression device:
Device type Auto decomp ----
Air filter oil grade: Engine oil ----
Carburetors:
I. D. mark 5LP1 00 ----
Main jet (M.J) Carburetor #1 : #140
Carburetor #2 : #145----
Main air jet (M.A.J) #130 ----
Jet needle (J.N) 5ND16-56-3 ----
Needle jet (N.J) P-6M (#826) ----
Pilot air jet (P.A.J.1) Carburetor #1 :...

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SPEC
Cooling system:
Radiator core
Width 219 mm (8.62 in) ----
Height 300 mm (11.8 in)  ----
Depth 16 mm (0.63 in) ----
Radiator cap opening pressure 95 ~ 125 kPa (0.95 ~ 1.25 kg/cm
2, 
13.8 ~ 18.1 psi)----
Radiator capacity 0.55 L (0.48 Imp qt, 0.58 US qt) ----
Coolant reservoir
Capacity 0.29 L (0.26 Imp qt, 0.31 US qt) ----
From low to full level 0.165 L (0.15 Imp qt, 0.17 US qt) ----
Water pump:
Type Single suction centrifugal pump ----
Reduction ratio 33/34 (0.971)
Lubrication chart:Item...

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SPEC
Cylinder head tightening sequence:Item Standard Limit
MAINTENANCE SPECIFICATIONS 

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SPEC
Tightening torques
Part to be tightenedPart 
nameThread 
sizeQ’tyTightening torque
Remarks
Nm m·kg ft·lb
Cylinder head (exhaust pipe)
Stud boltM6 4 7 0.7 5.1
Cylinder head Bolt M9 4 38 3.8 27
Bolt M9 2 38 3.8 27
Bolt M6 1 10 1.0 7.2
Spark plug — M12 1 18 1.8 13
Cylinder head cover Bolt M6 17 10 1.0 7.2
Camshaft end cap Bolt M6 1 10 1.0 7.2
Oil check bolt — M6 1 7 0.7 5.1
Tappet cover (exhaust) — M32 2 12 1.2 8.7
Tappet cover (intake) Bolt M6 4 10 1.0 7.2
Cylinder Bolt M10 2 42 4.2 30
Bolt M10...

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SPEC
Bearing retainer Screw M6 4 7 0.7 5.1LT
AC magneto rotor Nut M14 1 150 15.0 110
Starter clutch Bolt M6 6 16 1.6 11
LT
Balancer driven gear Nut M18 1 140 14.0 100M
Use a lock 
washer.
Primary drive gear Nut M20 1 150 15.0 110M
Use a lock 
washer.
Clutch spring Bolt M6 5 8 0.8 5.8
Clutch boss Nut M20 1 90 9.0 65
Use a lock 
washer.
Pull lever shaft Bolt M6 1 7 0.7 5.1
Drive sprocket Nut M18 1 70 7.0 50
Use a lock 
washer.
Oil seal retainer Bolt M6 2 10 1.0 7.2
Shift drum segment Bolt M8 1 30...

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SPEC
CHASSIS
Item Standard Limit
Steering system:
Steering bearing type Ball and race bearing ----
Front suspension:
Shock absorber travel 110 mm (4.33 in) ----
Fork spring free length 316.5 mm (12.46 in) ----
Spring fitting length 293.5 mm (11.56 in) ----
Spring rate (K1) 19.6 N/mm
(2.00 kg/mm, 111.92 lb/in)----
Spring rate (K2) 29.4 N/mm
(3.00 kg/mm, 167.87 lb/in)----
Optional spring No ----
Rear suspension:
Shock absorber travel 100 mm (3.94 in) ----
Spring free length 273 mm (10.75 in) ----...

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SPEC
Front disc brake:
Type Dual ----
Disc outside diameter × 
thickness 161.0 ×
 3.5 mm (6.34 ×
 0.14 in) ----
Pad thickness inner 4.2 mm (0.17 in) 1 mm 
(0.04 in)
Pad thickness outer 4.2 mm (0.17 in) 1 mm 
(0.04 in)
Master cylinder inside diameter 12.7 mm (0.50 in) ----
Caliper cylinder inside diameter 32.03 mm (1.26 in) ----
Brake fluid type DOT 4 ----
Rear disc brake:
Type Single ----
Disc outside diameter × 
thickness 220.0 ×
 3.6 mm (8.66 ×
 0.14 in) ----
Pad thickness inner 4.5 mm (0.18 in)...

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SPEC
Tightening torques
Part to be tightened Thread sizeTightening torque
Remarks
Nm m·kg ft·lb
Engine bracket (upper) and frame M8 33 3.3 24
Engine bracket (upper) and engine M10 40 4.0 29
Engine bracket (lower) and frame M10 56 5.6 40
Engine bracket (lower) and engine M10 56 5.6 40
Engine bracket (middle and lower) and engine M10 56 5.6 40
Swingarm pivot shaft, engine and frame M16 95 9.5 68
Rear shock absorber and frame M10 32 3.2 23
Relay arm and swingarm M10 32 3.2 23
Connecting arm and frame...

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SPEC
HINWEIS:NOTE:
Apply locking agent (LOCTITE®) to ring nuts threads.
1st: Tighten the inside ring nut 55 Nm (5.5 m  kg, 40 ft  lb).
2nd: Tighten the outside ring nut while holding the inside ring nut 190 Nm (19 m  kg, 140 ft  lb).
3rd: Loosen the inside ring nut while holding the outside ring nut 240 Nm (24 m  kg, 170 ft  lb).Front brake master cylinder and brake lever M6 6 0.6 4.3
Front brake master cylinder and brake hose M10 27 2.7 19
Brake hose joint and frame M6 10 1.0 7.2
Bleed...

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SPEC
ELECTRICAL
Item Standard Limit
Voltage: 12 V ----
Ignition system:
Ignition timing (B.T.D.C.) 12°/ 1,500 r/min ----
Advancer type Digital type ----
C.D.I.:
Magneto model/manufacturer F4T260/MITSUBISHI ----
Pickup coil resistance/color 445 ~ 545 Ω
 at 20 °C (68 °F)/
White/Red – White/Green----
Rotor rotation direction detection coil resis-
tance/color0.069 ~ 0.085 Ω
 at 20 °C (68 °F)/
Red – White/Blue----
C.D.I. unit model/manufacturer F8T37971/MITSUBISHI ----
Ignition coil:
Model/manufacturer...