Topic: Is this what is happening inside the oil reservoir?

[SKOL]

Pleas excuse my 3 year old drawing. But I needed to visually conceptualize what the inerds of the oil tank looks like. Now things may not be in the correct place, spatially, but where they are located in this drawing would still produce a functioning oil tank correct? The vent tube in the oil tanks on the k6 are actually at the bottom of the tank, which means they have a tube running up to the top of the tank inside, much like the return tube?



Also, could the vent tube be eliminated if a vented filler cap was used? In which case, what would you do to the vent spigot on the bottom crank case that the vent tube goes to? Seal it?

[flybox1]

Dont seal either end of the vent, or you better be sure there is nothing in your engine to block the oiling circuit.
Any oil pressure/level buildup in the oil tank needs a place to go, and the safest place is into the rear of the case and into the sump.
NOT on your rear tire 

[SKOL]

Dont seal either end of the vent, or you better be sure there is nothing in your engine to block the oiling circuit.
Any oil pressure/level buildup in the oil tank needs a place to go, and the safest place is into the rear of the case and into the sump.
NOT on your rear tire 

Thatnks Fly, how about in terms of a custom application. Say an oil tank that utilized a vented filler cap. The tank would have no need for a vent tube, so what would need to be done to the crankcase spigot?

[flybox1]

I dont think you quite understand the reason for the 'vent' tube on the oil tank to the case.......its to give any oil buildup in the tank a place to go other thank out the filler cap. 
If the vent tube nipples were plugged up, and you had a 'vented' oil cap...sure, air would escape out the vented cap, but so would the oil when the buildup eventually reached it.

[flybox1]

By all means...plug them up if you are confident there is nothing in your engine, like case sealant boogers, or pieces of old cam chain rollers and such to block oil return holes/jets   

[SKOL]

I dont think you quite understand the reason for the 'vent' tube on the oil tank to the case.......its to give any oil buildup in the tank a place to go other thank out the filler cap. 
If the vent tube nipples were plugged up, and you had a 'vented' oil cap...sure, air would escape out the vented cap, but so would the oil when the buildup eventually reached it.

So the air and any built up oil travel from the vent tube to the bottom of the case, that air eventually being let out from the vent tube at the top of the cam case that is exposed to the environment.


Hmmm... I guess I just thought the use of a vented cap would regulate air pressure in the tank causing oil to not build up inside high enough to go over the return tube as well as  go high enough to reach the cap. Which, I guess in a fully functioning oil tank, the oil reservoir reaches higher than the return tube, as well as reaches the cap, thus the need for a vent tube, which I guess is operating more as an overflow/vent?

[SKOL]

By all means...plug them up if you are confident there is nothing in your engine, like case sealant boogers, or pieces of old cam chain rollers and such to block oil return holes/jets   

I have my engine cases split and everything removed. Replaced primary and cam chain tensioners. Oil passages have been gone through extensively. I was just curious for when I start to reassmble, if I got a wild hair up my a** to use a custom tank, I wanted to wrap my head around the inner functioning of the stock reservoir to apply that logic to a custom tank.

[flybox1]

I dont think you quite understand the reason for the 'vent' tube on the oil tank to the case.......its to give any oil buildup in the tank a place to go other thank out the filler cap. 
If the vent tube nipples were plugged up, and you had a 'vented' oil cap...sure, air would escape out the vented cap, but so would the oil when the buildup eventually reached it.

So the air and any built up oil travel from the vent tube to the bottom of the case, that air eventually being let out from the vent tube at the top of the cam case that is exposed to the environment routed back to your airbox separator.   

Hmmm... I guess I just thought the use of a vented cap would regulate air pressure in the tank causing oil to not build up inside high enough to go over the return tube as well as  go high enough to reach the cap. Nope...air pressure buildup in the tank means the oil level is rising....and you have to have a place for that oil to go.  The overflow 'vent' tube down to the sump is the best place. The oil pump is submerged in oil.  there is no air for it to pump to build air pressure.  Whatever air is in the system including that which is suspended in the oil, wont change much, if at all Which, I guess in a fully functioning oil tank, the oil reservoir reaches higher than the return tube, as well as reaches the cap, thus the need for a vent tube, which I guess is operating more as an overflow/vent?

If your custom tank (vented cap) was large enough to hold say 4 quarts of oil, you eliminate any need for an overflow vent tube to the case.

[SKOL]

I dont think you quite understand the reason for the 'vent' tube on the oil tank to the case.......its to give any oil buildup in the tank a place to go other thank out the filler cap. 
If the vent tube nipples were plugged up, and you had a 'vented' oil cap...sure, air would escape out the vented cap, but so would the oil when the buildup eventually reached it.

So the air and any built up oil travel from the vent tube to the bottom of the case, that air eventually being let out from the vent tube at the top of the cam case that is exposed to the environment routed back to your airbox separator.   

Hmmm... I guess I just thought the use of a vented cap would regulate air pressure in the tank causing oil to not build up inside high enough to go over the return tube as well as  go high enough to reach the cap. Nope...air pressure buildup in the tank means the oil level is rising....and you have to have a place for that oil to go.  The overflow 'vent' tube down to the sump is the best place. The oil pump is submerged in oil.  there is no air for it to pump to build air pressure.  Whatever air is in the system including that which is suspended in the oil, wont change much, if at all Which, I guess in a fully functioning oil tank, the oil reservoir reaches higher than the return tube, as well as reaches the cap, thus the need for a vent tube, which I guess is operating more as an overflow/vent?

If your custom tank (vented cap) was large enough to hold say 4 quarts of oil, you eliminate any need for an overflow vent tube to the case.

I estimate it to be at around 3.8 quarts or so, what is stock, 3.5? I think I could get more out of it, I'm just sketching one for Sh*ts and giggles. If running pods, wouldn't the cam case vent have to be exposed to environment since there is no airbox?

[flybox1]

Run a small filter at the valve cover vent.

[SKOL]

Run a small filter at the valve cover vent.

Gotcha. Seems like incorporating the vent tube in a custom tank is a much smaller pain in the ass than trying to figure out a way to eliminate it

[ekpent]

 The 'cam case vent' on earlier pre 77 750's does not go to the airbox.

[SKOL]

The 'cam case vent' on earlier pre 77 750's does not go to the airbox.

Just routed back and down, terminating near the swingarm?

[flybox1]

Correct.