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I have a 69 Triumph 650 bonneville, I am now on the oil system. I know that I need a 5/16" line from the motor to the oil tank and also as a return to the motor, I know I need a 1/8'' line to the "rockers" on top of my engine. What I need to know is how much do restrict the 5/16", "in" line to the oil tank so that the 1/8" line to the rockers has the right amount of pressure?? Thanks for the Advice!
 

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I have a 69 Triumph 650 bonneville, I am now on the oil system. I know that I need a 5/16" line from the motor to the oil tank and also as a return to the motor, I know I need a 1/8'' line to the "rockers" on top of my engine. What I need to know is how much do restrict the 5/16", "in" line to the oil tank so that the 1/8" line to the rockers has the right amount of pressure?? Thanks for the Advice!
Do not go restricting anything!! There is plenty of return line oil and pressure to make it to the rockers. If oil is making it there, look for blockages in the feed lines and/or shafts. RR
 

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The "restriction" is already built into the system. Make sure there's no kink in the rocker feed.
I believe the original tank lines were 3/8"? so you'll increase pressure slightly with 5/16"
that's not a bad thing
 

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Let's not confuse missdolly more than necessary.
The hoses that feed oil in and out of the engine are 5/16" I.D.The hose closer to the outside of the timing cover feeds oil into a unit engine (it's different on a pre-unit).The steel tube feeding the rockers is 3/16" O.D.,so the hose connecting to it is 3/16" I.D.

The return line has a restriction inside the standard oil tank.The end of the pipe inside the tank is crimped closed and there is a 7/32" hole drilled in the side of the pipe to let oil escape.This causes enough pressure in the return line to push oil up to the rocker shafts.

You can create a little more pressure with a smaller outlet on the end of the return line,but keep the outlet hole at least 3/32" or bigger.I've not used less than 7/64" hole,which gives 16 times as much pressure and 4 times the flow to the rockers.

If the engine is warm and you hold the rocker feed line a foot above the rocker spindles,oil still should come out of the line.If you hold it higher,there may not be enough pressure to lift the oil that high.That's enough pressure.
 
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