My Polaris Sportsman 500 is slipping in forward but not in reverse. When starting out slips and when I am up to speed and give it gas it just revs. Any ideas?

 

Welcome! Could be as simple as a belt needs replacement or clutches may need to be checked out, especially the rear (driven clutch) ramp buttons and helix wear. Look here on your model under "drive and driven" clutches as to parts involved. Browse OPT