Yamaha RAPTOR YFM125RA, Service Manual, Page: 29 / 300

ENGINE SPECIFICATIONS
2-6
Free length (exhaust) 47.06 mm (1.85 in)
Limit 44.71 mm (1.76 in)
Installed length (intake) 25.60 mm (1.01 in)
Installed length (exhaust) 25.60 mm (1.01 in)
Spring rate K1 (intake) 8.01 N/mm (0.82 kgf/mm, 45.74 lbf/in)
Spring rate K2 (intake) 9.33 N/mm (0.95 kgf/mm, 53.27 lbf/in)
Spring rate K1 (exhaust) 8.01 N/mm (0.82 kgf/mm, 45.74 lbf/in)
Spring rate K2 (exhaust) 9.33 N/mm (0.95 kgf/mm, 53.27 lbf/in)
Installed compression spring force (intake) 160.00–184.00 N (16.32–18.76 kgf, 35.97–
41.36 lbf)
Installed compression spring force (exhaust) 160.00–184.00 N (16.32–18.76 kgf, 35.97–
41.36 lbf)
Spring tilt (intake) 2.5
°
/2.1 mm (0.08 in)
Spring tilt (exhaust) 2.5
°
/2.1 mm (0.08 in)
Winding direction (intake) Clockwise
Winding direction (exhaust) Clockwise
Piston
Piston-to-cylinder clearance 0.019–0.035 mm (0.0007–0.0014 in)
Limit 0.15 mm (0.006 in)
Diameter D 53.997–54.029 mm (2.1259–2.1271 in)
Height H 4.5 mm (0.18 in)
Offset 0.50 mm (0.0197 in)
Offset direction Intake side
Piston pin bore inside diameter 15.002–15.013 mm (0.5906–0.5911 in)
Limit 15.043 mm (0.5922 in)
Piston pin outside diameter 14.991–15.000 mm (0.5902–0.5906 in)
Limit 14.971 mm (0.5894 in)
Piston-pin-to-piston-pin-bore clearance 0.002–0.022 mm (0.0001–0.0009 in)
Limit 0.072 mm (0.0028 in)
Piston ring
Top ring
Ring type Barrel
Dimensions (B
×
T) 1.00
×
2.10 mm (0.04
×
0.08 in)
End gap (installed) 0.15–0.30 mm (0.006–0.012 in)
Limit 0.40 mm (0.0157 in)
Ring side clearance 0.035–0.070 mm (0.0014–0.0028 in)
Limit 0.120 mm (0.0047 in)