I have X2 maybe best if RMAX guys answer that. On mine its underneath in small hole in skid plate not far from that plastic air intake cleanout that ppl have trouble with. My owners manual doesn't give location of it but service manual does. From X2, I imagine RMAX is same. Its a surprisingly small drain screw. Take radiator cap off so it can drain. Best to have an inch/ib torque wrench to reinstall that screw ... just 7.4 ft-lb or 88.8 inch-lb.No I didn't know about the drain screw, where is it located?