Just for reference, this bikes donĀ“t use a filter. The closest you get is a wire mesh screen over the oil pump pickup, which requires removal of the right crankcase cover, but should be done every now and then. While this screen is available from Honda, you can just clean it in solvent and dry it off. I also recommend using a magnetic drain plug. As for oil grade, I generally use a 20w50 synthetic motorcycle oil, but if you are in a temperature climate, 10w40 might work as well. Refill volume is usually just a bit over a quart.