I have changes my oil twice now and I find it hard to achieved the proper oil level in the sight glass, on both occasions it took a few add and remove to reach the line in the glass. Since then I have checked the oil level each time I start and finish a ride and the level will not be the same as when I started, at times it is either on the line, below or above the mark and sometimes covers the sight glass completely. How important is it to have the oil at the proper level, will it cause harm to the engine if it goes a little below the line or about the line or all the way up to the top of the glass. This is driving me nuts.