Engine Specifications - Yamaha YZ125 Owner's Manual

EAM20128

ENGINE SPECIFICATIONS

Engine
Combustion cycle
Cooling system
Induction system
Displacement
Number of cylinders
Bore  stroke
Compression ratio
Starting system
Fuel
Recommended fuel
Fuel tank capacity
Engine oil
Recommended brand
Lubrication system
Engine oil
Premix ratio
Transmission oil
Type
Quantity (disassembled)
Quantity
Cooling system
Coolant quantity
Radiator (including all routes)
Spark plug(s)
Manufacturer/model
Spark plug gap
Clutch
Clutch type
Clutch lever free play
Friction plate thickness
Wear limit
Plate quantity
Clutch plate thickness
Plate quantity
Warpage limit
Clutch spring free length
Clutch spring free length limit
Push rod bending limit
Drivetrain
Primary reduction ratio
Transmission type
Gear ratio
1st
2nd
3rd
4th
ENGINE SPECIFICATIONS
2-stroke
Liquid cooled
Reed valve
125 cm³
Single cylinder
54.0  54.5 mm (2.13  2.15 in)
8.6–10.7 : 1
Kickstarter
Premium unleaded gasoline (E10 acceptable)
8.0 L (2.1 US gal, 1.8 Imp.gal)
YAMALUBE
Premix lubrication
YAMALUBE 2R
30
Motor oil SAE 10W-40 type SG or higher
0.70 L (0.74 US qt, 0.62 Imp.qt)
0.66 L (0.70 US qt, 0.58 Imp.qt)
0.90 L (0.95 US qt, 0.79 Imp.qt)
NGK/BR9EVX
0.6–0.7 mm (0.024–0.028 in)
Wet, multiple-disc
7.0–12.0 mm (0.28–0.47 in)
2.90–3.10 mm (0.114–0.122 in)
2.80 mm (0.110 in)
8 pcs
1.50–1.70 mm (0.059–0.067 in)
7 pcs
0.20 mm (0.008 in)
40.10 mm (1.58 in)
38.10 mm (1.50 in)
0.30 mm (0.012 in)
3.368 (64/19)
Constant mesh 6-speed
2.385 (31/13)
1.933 (29/15)
1.588 (27/17)
1.353 (23/17)
2-2