This change I used 20w-40 Spectro 4 but I have no idea what the PO was using. He only owned the bike about a year or so and although he said the oil had been changed, it sure didn't look like it. I've used Mobil 1 T4, and I've had 9 Yamaha's over the years from a 1978 or so XS650 to a 2018...