Motorcycle Repair: Burnt valve?, valve question, oil tank

Question
QUESTION: Where do I find the oil filter on a 1977 sportster

ANSWER: If its electric start its under the oil tank cap. If its kick start then there isn't one unless someone has installed a remote one. Those are usually down by the front tire on the frame.

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QUESTION: I have one pipe smoking with oil in it and one pipe not smoking which has no oil in it.  One does one pipe have oil and not the other?  Is that a burnt valve?

Answer
That condition would be a valve guide problem, Either the valve seal went bad,came off or was never installed. Could be that your valve stem to guide clearance is worn to wide and oil is slipping through or your guide is cracked. For a valve to be burnt the bike would pop when running and also suck air in that pipe at different times during the engines revolutions.