Honda CRF50F 2004-2015 Service Manual page 98

SERVICE INFORMATION
GENERAL
• The cylinder and piston service can be done with the engine installed in the frame.
CYLINDER/ PISTON
• Camshaft lubrication oil is fed to the cylinder head through an orifice in the cylinder head, cyl inder and crankcase. Be
sure that this orifice is not clogged and that the O-rings and dowel pins
afe
in place before installing the cylinder.
SPECIFICATIONS
TORQUE VALUE
Cam chain guid e roller pin bolt
9.8 N'm (1.0 kgf·m, 7 Ibf·ft)
TROUBLESHOOTING
• If the performance is poo r at low speeds, check for white smoke in the crankcase breather hose. if the hose is smoky,
check for a seized piston ring.
Cylinder compression is too low, or engine is hard to start
• Blown cylinder head gasket
• Worn, stuck or broken piston ring
• Worn or damaged cylinder or piston
Cylinder compression is too high, or engine overh eats or knocks
• Ca rbon deposits on the cylinder head andlor p iston crown
Piston sounds
• Worn cyli nder, piston and/or piston ring
• Worn piston pin hole and piston pin
• Worn connecting rod small end
Excessive smoke
• Worn, stuck o r broken piston ring
8-3