My 500 has me confused. Should the sight glass show oil in it while it's idling? Sometimes it will and at other times it shows nothing. The atv was parked for 5 years due to health issues and when we got it out and started riding it smokes oil smoke and the more we ride it the worse it smokes. It didn't smoke before I parked it. No power loss and runs great. It has around 2600 miles on it and have always done the maintenance when it was due. Could the drain holes in the head be part of the issue or is it time for rings.