I have a 2001 polaris trail boss 325 in very good condition with low hours. Today when I started it up a heard a pop and noticed that the front valve cover blew off completely and what I believe to be oil was spitting everywhere. I then lightly put the cover back on and started it again and noticed a terrible burning smell and white smoke possibly from the oil that had leaked onto the front part of the exhaust? But more concerning, I noticed some sort of fluid leaking from the muffler in the back of the machine, what could cause these problems and where should I start to fix it?

 

Check that the crank case vent line isn't kinked or stopped up from the breather cover leading to the air box.May have been pressure build up or the valve cap may have been loose in the first place. You can't lightly put the breather cover back on or it will leak as you've seen. Spray the outside of the engine down with Gunk engine cleaner and wash off the oil. Get a new gasket for the valve cover. Item#8.

 

Vent lines all look good to me, how tight should the valve cap go? When I tighten it any more than hand tight it strips and pops out again, do I need a new cap? Also would any of this cause the fliuid I noticed coming from the muffler

 

Cleaned everything up and started up the machine again, white smoke from exhaust near engine and slight dripping by the muffler, also wet all around where the exhaust connects to the engine. Is oil somehow leaking into the exhaust, and how could this happen?

 

If the aluminum valve cap is stripped out then get another one along with a new o-ring.Just snug the new one down,don't crank down on it.I'd still get a new cam cover gasket,then see how it does.If when the engine is clean and dry and you have white smoke from the muffler,that could either be valve guide seals or blow by from the piston rings. This is where a leak down test would come into play. Same principle as what was done on this lawn mower engine.