Motorcycle Repair: cb900, valve stem seals, vacuum gauge

Question
my honda cb900 is using alot of oil and fouling plugs I think it might be worn valve stem seals as it doesnt smoke under power but you can smell oil on over run when coming to a stop and smokes when you take off again .I have balanced the carbs with vacuum gauge and set idle mixtures after all carbs were dismantled and cleaned but idle is erratic. Engine only smokes after idling or after over run or free reving otherwise has plenty of power and goes well. Would you know if you can do valve stem seals without taking head off

Answer
Ken, you didn't mention what year we're talking about but my guess is that you have to pull the engine for this repair and once it's out, getting the head off is only a little more work.  I'd recommend you do it right and pull the head.  You may have more going on than just bad seals.  If the guides are worn too much, you could break the head off of the valve if the valve isn't being centered on the seat when it closes.

Regards
Rich