GN4 all the way, I also think thereís no need for a higher performance oil since our engines are on the smaller side of the house and we are cruising, not racing hardcore off every acceleration stop and go all day everyday. Iíve also heard be careful with aftermarket oil filters cause each filter flows the oil at different rates and could lead to under or over lunrication which cuase mess your engine up over time. And never use regular car automotive oil. I hear they have way more friction reducing properties thatís not good for motorcycles. Which I was surprised how experts get to these down to a science. Cuase as a kid we never noticed a difference we would use 10w-30w automotive oil on my old Honda 50 , three wheeler 110, and old V twin 400 and never noticed a difference but since neither lasted the test of time and no longer have them guess thereís your sign. But they were fun while they lasted my childhood and high school times.