Pre war copper fuel and oil lines

[Chris Haynes]

I have found many original pre war bikes with copper fuel and oil lines. Jd's, Vl's, 45's, Knucks, and UL models. As far as I know copper was the only material used until the early '40's. I have heard of 1941's with aluminum lines but never found one. Gas tank crossover lines continued to be copper into the Panhead era. Does anyone have a pre war machine with the original copper lines still installed? They were originally nickeled.
While searching for any factory documentation of the Bruce found this document. Have a look at item number 9.

[sirhrmechanic]

Work hardening and breakage of copper lines is common on old engines. After bending, it's very important to anneal the lines to re-soften them. And plating (at least bright plating) is about the worst thing you can do. It was done all the time back in the day. But it's terrible for the longevity of the copper.

These days on car engines, we replace almost all the copper oil lines as a matter of course. A few years ago, we had an extra oil line (to the piston skirts) break due to age and fatigue on a new engine. It cost a set of bearings because the owner didn't notice that every time he stepped on the gas, he was dumping out his oil. Lost a couple of mains and 1 rod on a new engine. That was expensive.

Now all copper lines are re-annealed, pressure checked... but usually just replaced. We re-use the original brass fittings, however. Just the copper lines get re-made.

For bikes that vibrate a lot more than some of our big 6's... the problem can only be amplified. Definitely worth addressing during restoration.

The tape thing from Chris is interesting. That would be a total help as it would damp out harmonics that cause work-hardening and breakage. Wonder how the judges would treat it? Fine, I guess, as long as you had a copy of article 9 with you!

Cheers,

Sirhr

[Chris Haynes]

The tape thing from Chris is interesting. That would be a total help as it would damp out harmonics that cause work-hardening and breakage. Wonder how the judges would treat it? Fine, I guess, as long as you had a copy of article 9 with you!

Cheers,

Sirhr

Tape on the lines of a restored bike would be incorrect as it didn't leave the MoCo with tape on the lines. On an unrestored machine it would be allowed.

[kunzog]

I knew a mechanic and inventor that soldered washers every half inch or so to the copper oil lines of his Harley to try to cool the oil, dont know if it helped or not but seemed like a good idea in the 50's.

[exeric]

If you had a Volkswagen in Florida, you put a clothespin on the gas line to minimize vapor lock.

[dlm32]

I bent some copper lines for my board track racer. How do I re-annel them? I used to do copper head gaskets by putting them in the oven at 350 degrees for a while.

[sirhrmechanic]

First the washers... that would work very well. I had to scratch-build a radiator for a 1903 Curved Dash Olds and it involved soldering hundreds of copper washers onto pipes that had repeated 180 degree bends in them. Miserable job. But works well!

To re-anneal, use a propane torch (two of them used on opposite sides of the pipe is even better) and heat the copper to red hot. Then quench it in water. It does not have to be red hot when you quench it. It will air anneal fine. This is the opposite of tempering steel, btw where quenching hardens. Quenching copper softens it, but so will air cooling. The water just works a bit better.

The copper will come out looking blotchy and nasty, but will polish out just fine. Use Scotchbrite, steel wool, 600 grit sandpaper and then copper polish. Resist temptation to use a wheel, because it will catch on the pipe and bend it into a pretzel.

BTW, annealing is also done regularly as you are bending lines. In copper, you get 1 good bend, then it's work-hardened. You can't bend back. But if you anneal, you can work it almost endlessly.

Hope this helps,

Cheers,

Sirhr