Good day and thank you to the members here,
I recently aquired a 95 sportsman and after servicing the fluids, The motor began smoking excessively and the CB oil immediately started leaking into the cylinder (found the missing oil by pulling the drain plug), I do hear the rattling at high speeds. I already ordered the gaskets kit that was recommended by OPT to reseal the 3rd case and WP. I also ordered the large bearing behind the CB assy just in case. I plan on removing the CB assy and sending it for service (recommended by OPT). My questions are:
1) will the CB service fix my problem of CB oil leaking into the cylinder and being burned?
2) How hard is it to replace the crank bearings? If i understand correctly, its ok for slight side to side movement of the crank but not up and down?
3) what is the urgency of this repair:
Previous owner kept oil in the CB hence the abundance of exhaust smoke.
I hear a small amount of rattle at higher speeds/rpms, not bad though.
Cooling system working with no coolant leaking into CB or anywhere so I was thinking I could ride it as is temporarily and put small amount of oil into CB reservoir more frequently to coat the bearing. Just until I make time for the repair??
Again, thank you for the wealth of knowledge that is shared here. special thanks to OPT.

 

Counter balancer oil would have to travel through the crank seal to get into the lower crank case. If you replace the outer case seal,replace the crank seal while you're at it. The crank should have no up and down travel and really shouldn't move side to side either. Rather than try to repair this machine one section at a time,I'd tear it down and do it right as it may involve new crank bearings and possibly a new rod kit also. Pain in the rear to repair something and have to tear it back down again to repair something else. Item#36 are the two seals involved.

 

When I 1st checked the CB oil, it was empty so, I put 100cc of 10w30 and she immediately started smoking alot. So much so, that the plug fouled and it wouldnt run smoothly. I opened up the drain next to the CB drain and the 10w30 came streaming out so it must be leaking through the crank seal as you said.
The previous owner rebuilt the top end but obviously didn't give any attention to the bottom end.
how much of a chore is it to replace the crank bearings?

 

If you look at that parts break down the whole engine has to be taken apart to replace the 3 crank bearings. It's best to do this on this particular engine because of all the moving parts its has. More than many 4 strokes out there.I would check very carefully for any up and down play on the rod itself. If any amount of play is noticed the rod would have to be replaced also. I've seen too many people just replace crank bearings,new top ends only to have lower rod bearings spit out the small roller bearings up into the cylinder. Then the new top end is destroyed and engine has to be completely torn apart again. Not worth the risk when you can just get a new rod kit and have a machine shop or dealer install it while the cylinder is being bored for a new over size piston. It's like that old quote,pay me now to do it right or pay me more later..