[mwebb]

Originally Posted by Old Tele man

...bad value stem seals let the engine "suck" oil into the cylinder.

while this is very correct ,
it gets worse .
the leaking valve stem seal on the exhaust valve allows oil to drip down the valve stem , where it gets baked on causing an increase in valve stem OD which leads to the exhaust valve sticking in the exhaust valve guide which ends with catastrophic engine failure , when Mr Piston slams into Mr stuck open exhaust valve .

i have found
most / all owners of older hondas that require valve adjustments as part of normal service ,
never ever perform valve adjustments and most do not even know that such a thing exists - ?
i have seen many a honda engine that needs a valve job because of lack of proper maintenance -

when you do get around to performing your valve adjustments
grab the upper spring plate and wiggle it , when that cylinder is at TDC ,
there should be no perceptible wiggle IF the valve guides are still good ,

when you get the cyl head back from the machine shop , before you pay for the repair , wiggle the upper spring plate on all the exhaust valves , if they wiggle .
the machine shop did not replace the valve guides -
punish them accordingly .

the vacuum gauge is your friend it will reveal engine problems and it is easy to use and easy to connect and cheap , works on any engine .