The owner manual on the Rebel calls for 10w30 or 10w40. Being in Florida, air cooled engine and stuck in traffic when it's a 100 out. I agree on the 10w40. I remember the old Honda ATC four stroke Hondas they got whatever dumped in them and oil changed whenever they got sunk and had water in the crankcase. They still ran forever. Honda four strokes are very forgiving.