I have a 1995 Xplorer 400 2 cycle. I rebuilt the engine a year ago and it runs great. After I ride it and park it in the garage, I see oil drips & some times small puddles under the machine. Since its a 2 cycle, it can only be 2 cycle oil but its black and gritty. I traced it down to the vent line that comes from the chamber that drives the water pump and counter-balancer. The counter balance has a small (a few onces) of 10w-40 oil that is meant for lubing the counter balancer gears in the same compartment. This counter balance lube oil does not seem to be leaking (I've checked with the oil dip stick). So, I don't know where the oil in the vent line is coming from. I thought maybe the oil pump may be leaking into the counter balance chamber and vaporizing (the counter balance drives the oil pump). Has anyone else had the problem (if it is a problem)? If yes, how did you fix it.

 

Counter balancer cavity only hold 100ccs (little under 3.5 ounces) Possible that as it's running pressure builds up and out towards the end of the tube if you have too much oil. When you kill it,the oil drips out. Just clean everything up and place a clean piece of card board under the bash plate to help find the leak. If the water pump seals leaks into the cavity you'd have milky oil all over the floor.Plus you might even try a lighter weight of oil like 0w40 and see if it helps.

 

OPT,

Thanks for the quick reply! I've been monitoring this oil leak for several months with fresh cardboard. It is definitely from the vent/breather tube which I have hanging down into the bash plate. The oil is dark/jet black and is very thin, almost watery, although I would not call it milky. After I ride it and park it overnight, a new oil puddle is there in the morning. There is enough oil for a 2 or 3” round puddle (more on the bash plate). I’ve been noticing that my antifreeze overflow tank has to be refilled quite frequently (i.e. after several long longs). As you mention, maybe the water pump seals are the problem. Hmmm… I know I put them in new when I rebuilt the engine a year ago. Funny thing is that the counterbalance oil on the dip stick still looks clear? I thought that if the water pump was leaking into the counterbalance compartment, this oil would be mirky too? I’m surprised this oil is not black like what is coming out of the vent/breather tube. Any other thoughts?

 

When you rebuilt the water pump if the counter balancer shaft had any any corrosion or wear marks/rings on it from the old seals new seals can leak right on past this into the cavity. I'd change oil to the thinner 0w40,keep the oil level just a tad lower than the top of the c/b dip stick full mark(75ccs or so instead of 100ccs) and see how it does. If it still drips out,then I'd suspect the w/p seals are leaking.If you installed the seals right on the rebuild,back to back with the correct seal facing outward,then there is a place online that can build up the c/b shaft if that ends up being the problem.http://www.ebay.com/itm/Polaris-ATV-400-350L-counter-balance-shaft-water-pump-REPAIR-balancer-/300941567648?pt=Motors_ATV_Parts_Accessories&hash=item461183e6a0&vxp=mtr