90/90 21, 130/90 16 Shinko SR777 Reinforced A/B Front & Rear Tire Kit - 2 Tires budpan1966 (160). 3.50-19 Shinko SR241 Series Dual Sport Front/Rear Tire ihave35cents (1301).
Tire sizes 130/90-16, 150/80-16, 160/60R-18, ? 100/90-19, 130/60-19, and 80/90-21 are 4-ply rated.