Honda 954 Service Manual page 255

Remove the bolts and breather separator and gasket. BOLTS
Check the PAIR check valves for wear or damage,
replace if necessary.
Remove the cylinder head cover (page 8-5).
Avoid damaging the c a m pulse generator while
removing the camshafts, remove the bolt and cam
pulse generator from the cylinder head.
Remove the timing hole cap and O-ring.