No that's the breather that comes from the petrol tank to the cylinder

They never changed the engine at all, the pipe comes off the 2 stroke bottle then to the nipple on the clutch case, the bleed screw is on the case too

 

Found this post after trying to jog my memory on my son's 1984 LT50.Never had to tear it down,so was a little foggy on the oiling system. See if this helps..


"The LT's oiling system is gear driven, and I don't see how it could be adjusted short of drilling out the cases and cylinder in hopes of getting more oil to the intake. If you aren't getting oil into the cylinder, it's probably blocked somewhere, as the gear driven setup it pretty stout.

Unlike most systems, the LTA50's oil is injected into the airstream after the carb, maybe 1/8" from the cylinder itself. If you pull the cylinder off, you'll see a very small hole on the top of the cases where the cylinder meets it. Oil comes out of the tank, into a banjo fitting on the right side case, down into the pump, then through a passage in the cases ending up in a small hole drilled into the bottom of the intake port, right before it enters the cylinder.

To disable the injection is ultra easy. Pull the banjo fitting out and replace it with a bolt. Optional would be to pull the case and push the pump gear away from the transmission gear. I noticed no power difference in doing so.

Check to make sure oil is making it into the banjo fitting. Most likely the oiling hole in the intake has gotten plugged from carbon buildup, or the little motor got so hot it seized even with the lube system working. These motors are well known for having carbon buildup issues, especially when they've been run in restricted mode. I have had great carbonless results with Motul 600, using it both in the injection and now in premix. Make sure you're not running a BPR4H plug, that's one really hot plug. The BR5H or even a BR6H are much better choices.

When re-assembling the motor, make sure the base gasket does not block the oiling hole. You may also want to drill a hole in the intake skirt for more power."