Just purchased one of these and I have a few questions: Went to change the air filter and it fell apart, but there were two pieces of the foam wrapping the wire cage - Normal? In addition there was about an inch of oil in the bottom of the air filter box - again - Normal? The backing piece of plastic for the wire cage was laying in the bottom of the filter box and the bolt was also in the oil. I am also looking for a recommendation on what to do with the machine as far as maintenance, it runs well, shifts fine, needs a new battery, but what else should I be checking? The previous owner had it for over 25 years and does not have any records or memory of the last oil change or any other maintenance other than needing to replace the battery a couple of years ago and placing a car battery on the front rack and running wires to the starter. Learning curve is sharp, but looking forward to the experience. Thanks for your input.