Topic: Oil smoke problem

[maliveline]

hey dudes so heres my question.  I have a 72' cb750.... theres a black hose that comes out of the crankcase im guessing.... it basically acts as a vent to allow air to escape probably because presure is building up from heat. anyway i used to have a 76 hondamatic and the hose from the crankcase plugged right into the air box. however, on my 72' the hose is just strapped to the frame and the end of the hose just kinda hangs freely under my seat. this means when i ride around and the bike gets hot there is heaps of oil smoke pouring out of this hose. you dont really notice it unless you are stopped then the bike appears to be smoking. also the oil seems to be condensing everywhere on the rear of the bike and my bike is constantly dripping oil when its parked....
I took my tank off to look to see if i could plug this hose into my air box like how it was done on my 76 but i can't find an inlet anywhere. is this a problem i have to live with or what??

[KingCustomCycles.com]

That hose should be vented to the atmosphere on a 72, I believe.  It is a crankcase vent and allows pressure from the combustion chambers, blowby, to escape without pressurizing your low end and causing all sorts of leaks.  My 69 has that hose going to the oil tank, on the backside where the nipple is hard to see.  Your Hondamatic had it acting as a PCV valve of sorts and was burning the oil vapor to reduce emissions.  That being said, if you have more than a few drops, it is excessive.  I would suggest a compression test to determine if your rings are sealing properly. 

[maliveline]

so that hose should plug into the oil tank?

[KingCustomCycles.com]

If your oil tank is the type with a fitting (nipple) on the back.

[maliveline]

its a stock 72 you tell me

[ekpent]

The hose that looks like it is going under your seat and should vent down in the swing arm area is hooked to the vent nipple that is up in the back of the middle of the valve cover,cam sprocket area and the tube at the bottom back of engine into the oil tank.

[maliveline]

so the hose thats under my seat just hangs freely out in the open to blow oil smoke all over my swing arm?

[KingCustomCycles.com]

It should not be blowing anything except water condensation and the occasional gas fume.  You have engine internal problems, compression test is in order.