Engine Bogging

The hose that terminates under the hood is the breather for the gearbox.

If it drips oil then either the box is over full, you are overheating or you have a leaky crankshaft seal.

You need to drain the gearbox and refill with 650ml of oil.

Overheating can be caused by an air leak making a lean mix!

I also recommend that you sdo a leakdown test.

If you have been riding without an air filter or a bit of rag stuffed in the air box, it is very possible you are overheating, and doing heaps of damage to the top end.
 
Thanks For the info, I am going to wait for my filter to con in next week along with the drain plug and washer for the crankcase drain.