For 4T engine only:
coil level is too high
doil level is too low
eoil does not interchange
coil route is blocked
dinsufficient oil pumping from
oil pump
cpiston and cylinder worn out
dmixture is too lean
ebad quality of the fuel
ftoo much carbon in the combustion room
gignition timing is too early
ctoo much carbon in the combustion room
dbad quality of the fuel
eclutch slip
fmixture is too lean
gignition timing is too early
Check the oil level in crankcase
Is too much or dirty
Oil level is normal
Oil level is