got a 2000 polaris sportsman 335 that is leaking oil out a little hole underneath the crankcase in the housing that the crankcase cover goes on. look like maybe a weep hole. no threads in it and if you lie under the atv you can look op onto the hole. any idea the cause or repair needed thanks in advance.  

the old trailboss 2 cycle machiens had this and it was to drain any 2 cycle oil from the crankcase that may have accumulated.
though all of these had threads and a screw.
you can download the Service manual here for this machine and have a look at what it is.


http://manuals.dqt.be/index.php?option=com_remository&Itemid=36  

I THINK ITS THE OIL SEAL LEAKING HOW HARD IS THAT TO REPLACE THANKS GAIN