Newbie oil question, sorry in advance!

Pooh

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I've built by first CB750 chop. Amen savior, P&P Girder, 836 kit. My question concerns the nipple on the back of the motor...
My aftermarket oil tank has the two lines that connect to the engine, no prob there. A third, smaller diameter spigot protrudes from the bottom of the tank. I've read a hundred threads concerning how the CB vents but can't get a clear answer. I connected the tank spigot to the nipple on the back of the motor with clear vinyl tubing. When the bike idles, oil doesn't flow but kinda "percolates" from the tank to the nipple. Is this correct? Thanks
 

dirtdigger

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In the stock bike with the stock oil tank the nipple on the back of the motor goes to the air/oil separator in the oil tank. When I build a bike not using the stock tank I just vent the tank to atmosphere and vent the nipple on the motor to atmosphere with a short hose or if room I put a little filter on it. The motor really only vents at the valve cover but its a dry sump motor so it natrually vents well anyway. Dont really know how your tank is built and what they intended the nipple for...maybe just a tank vent not meant to be hooked to anything.
 

Pooh

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In the stock bike with the stock oil tank the nipple on the back of the motor goes to the air/oil separator in the oil tank. When I build a bike not using the stock tank I just vent the tank to atmosphere and vent the nipple on the motor to atmosphere with a short hose or if room I put a little filter on it. The motor really only vents at the valve cover but its a dry sump motor so it natrually vents well anyway. Dont really know how your tank is built and what they intended the nipple for...maybe just a tank vent not meant to be hooked to anything.
In the stock bike with the stock oil tank the nipple on the back of the motor goes to the air/oil separator in the oil tank. When I build a bike not using the stock tank I just vent the tank to atmosphere and vent the nipple on the motor to atmosphere with a short hose or if room I put a little filter on it. The motor really only vents at the valve cover but its a dry sump motor so it natrually vents well anyway. Dont really know how your tank is built and what they intended the nipple for...maybe just a tank vent not meant to be hooked to anything.
Ah, ok. Guess I need to figure out why oil is dripping from that spigot coming from the bottom of the oil tank then. It doesn’t appear to be over-filled. The tube travels up inside the tank and ends just below the top of it, so it’s obviously a vent. If I plug that spigot and rev the motor, the pressure pops the cap off.
 

dirtdigger

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I kind of think that line probably should go to the nipple on the back of the motor.... most people dont really use clear tube so im guessing most dont really see what goes on in the tube. If it works fine and keeps the cap from blowing off while its connected to the back of the engine then I would think it will work fine.?
 

Pooh

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I’m using the clear line just to see how much, if any, oil was transferring. Is is it ok for oil to go into the nipple on the back of the motor?
 

dirtdigger

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Yes that is what it is for, oil is supposed to drain out of the separator in the stock tank back to the engine
 
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