Yamaha XP500 2001 Service Manual page 95

MEASURING THE ENGINE OIL PRESSURE
Engine oil pressure Possible causes
Below specification
Above specification
7. Install:
S main gallery bolt 1
3-26
CHK
ADJ
Faulty oil pump
Clogged oil filter
Leaking oil passage
Broken or damaged
oil seal
Leaking oil passage
Faulty oil filter
Oil viscosity too high
20 Nm (2.0 mSkg)