Inspect the cam chain guide in the following procedures:

Cam chain guide / cam chain tensioner
removal and installation
Cam chain tensioner inspectionDTC “c28” (p1655): secondary throttle
valve actuator (stva) malfunction
Detected condition and possible cause
Detected condition
Possible cause
The operation voltage does not reach the stva.
Ecm does not receive communication signal from the
stva. Stva can not operate properly or its motor locked
Stva malfunction.
...
Drive chain related components
Drive chain
Engine sprocket
Rear sprocket
Dust seal
Bearing
Retainer
Sprocket mounting drum
Wheel damper
145 N·m (14.5 Kgf-m,
105.0 Lbf-ft)
60 N·m
(6.0 Kgf-m, 43.0 Lbf-ft)
Apply grease
Apply thread lock to
thread p ...
Oil pan / oil pressure regulator / oil strainer
removal and installation
Note
the oil pan/oil strainer/oil pressure regulator
cannot be serviced with the engine installed
in the frame.
Removal
Remove the engine assembly from the frame. Refer to “engine assembly
removal” in section 1d .
Remove the plate (1).
Remove the oil pan ...