Yes i have 15w40 in there now,it performs very well,a warrior gets red hot when riding in the summer,burns my legs when i have shorts on,i have also ran Mobil 1 15w50 red cap,Mobil 1 15w50 EP, Amsoil 20w50, Super Tech 15w40,may try a 5w40 Mobil 1 Turbo Diesel Truck this summer.
you just don't want a high Moly content in your oil,that could result in clutch slippage.
just pick a 15w40 or 5w40 and ride,your rig will be protected well.
change oil often ATV's and some MC are tough on oil,i change two three times a summer depending on how much i ride.