This info from the owner's manual for my son's 09 Recon that he's getting for Christmas:
Oil Capacity: 1.6 quarts after draining.
2 quarts after a rebuild
Oil suggested: SG or higher rating but must not have "Energy Conserving" in the
round label on the container. SAE 10w-30, JASO T 903 Standard
MA, Pro Honda GN4 or an equivalent motorcycle oil.
Spark Plug: NGK DPR8EA-9 or DENSO X24EPR-U9 (standard plug)
Spark Plug Gap: 0.031--0.035"
Valve Clearance: intake: 0.005"
exhaust: 0.005
Idle speed: 1,400 + or - 100 rpm
You can use 10w-40 oil also per the manual in warmer temps. I will use Shell Rotella synthetic 5W-40 when I change the oil the second time in this new Recon. I use it in all the other atvs as well as my Yamaha V Star motorcyle with great results. Shell oils are now rated JASO MA as well.