possible oil pressure problem

1981 kz305 csr-a1

the bike runs for a while, then seems to overheat and just shuts off. i popped the valve adjustment plugs off yesterday while the bike was running, and it looked awfully dry in there. i expected much more oil.

i assume i should be able to see plenty of oil in the upper end, right? how can i check oil pressure on this bike?

i'm not sure i'm remembering right, but this might have begun the last time i changed the oil and filter. anybody have any idea if i might have put something in wrong to cause this?

thanks!
eric

p.s. - i also replaced the clutch discs about the same time. anything i could have screwed up there that would cause this?

Check the oil level again,if good, on non
spin/on oil filters,omitting an 'o'ring or
washer can let oil drain back into the sump
area and not get to the topend.be sure that
you installed everything correctly.On high
mileage motors a plugged oil gallery is also
a possability.