Brass tubing fuel lines..yay/nay

Bucky685

Bucky685

Been Around the Block
I am building a '74 CB360. I am planning on using 1/4" Brass Tubing/Brass double ferrel compression fittings for my fuel line.

I have googled it, and haven't really found a answer.

Has anyone on here, used brass tubing for there fuel lines? Is it a good practice?

Can anyone point me to the proper brass tubing to use?

Like this>>
honda_cb360_bobber_engine-detail_troy-helmick.jpg
 
I tried it and it didn't work out so well. You need some really high quality compression fittings (like Swagelok) to pull it off. Copper tubes, like on Willow, work out a bit easier.
 
Willow, above used copper where it shows, with that loop for vibration and just before the carbs it changes to rubber, if you completely hard mount the tubing it will split from vibrations.
 
Sonreir said:
I tried it and it didn't work out so well. You need some really high quality compression fittings (like Swagelok) to pull it off. Copper tubes, like on Willow, work out a bit easier.
Click to expand...

Would flare fittings be a better option? I was thinking Compression fittings since that is what I'm familar with work.

The one thing I've read about copper is it will work harden and develop cracks.
 
Most brass tubing will tend to kink when you bend it.

Brass tube for horns, (like trumpets, trombones,) are filled with water, then frozen before bending. It prevents the tube from collapsing. Make sure the tube is annealed, first. Most brass tube is pretty darned rigid before annealing.

As far as connecting it goes, a compression fitting would probably be best, but I would solder the ferrule onto the tube rather than depend on the ferrule itself to seal.

I don't know that you would be able to flare it without cracking it. Maybe a double flare like is used for brake lines?

I imagine that brass would work harden similar to copper. Don't know that for a fact, however.
 
After doing a bit more research. People are using cooper fuel lines not brass. The biggest thing is not over working the tubing. And adding some rubber hose and pig tails to reduce vibration..

So it looks like if i excuite it correctly. I should be good to go.

Thanks for the advise fellas!
 
The other option is to use Copper Nickel tubing NiCopp. Which is DOT approved for brake lines. (which gives me a better feeling!) It how ever is much more $$ than clear tubing..

http://www.jegs.com/i/JEGS-Performance-Products/555/635802/10002/-1?parentProductId=2111534
 
Another option would be to use regular automotive tubing, bend it, shape it. Then take it to get coated.

Check out what type of coatings an electro-plater near you will offer. All the looks but with no loss of performance. Still the flexible end connections apply...
 
I guess its pure cosmetical? Because its not really a good solution anyway due to leaks/cracks/price.. PC would not be an option in that case.

I would go to an instrumentmaker, they work with brass/copper and so on on a daily basis. Go to the pro for best advice.
 
Instrument maker? I'd go stainless then...Most pneumatic instrument air is either cheapo plastic tubing, or really nice stainless. Stainless is thinner and lighter than equivalent copper. An intrument guy has the tool to bend it without crushing it. It would look like chrome plumbing.

the other option is stainless braided line. uses convention clamps, flexible, but nicer looking the PVC clear line.

Personally? I like the clear line. I like to see if the fuel is getting there.
 
I used brass fittings and copper lines and once the runs were confirmed I sweat soldered each coneection, the lead solder provided a minimum level of vibration flex. Some of the set ups I have done have lasted more than 10 years without a leak. I agree with all the previous recommendations of pigtails and short rubber unions to reduce nasty vibration issues.
 
cqyqte said:
I used brass fittings and copper lines and once the runs were confirmed I sweat soldered each coneection, the lead solder provided a minimum level of vibration flex. Some of the set ups I have done have lasted more than 10 years without a leak. I agree with all the previous recommendations of pigtails and short rubber unions to reduce nasty vibration issues.
Click to expand...


That's the way I would do it as well.
Worked well for years on majority of bikes from turn of the 1900 until copper got too expensive (probably 1950's~60's?)
Brass it too rigid because of the zinc content, it will work harden real quick and split
Copper will do the same as modern copper is different alloy now compared to 1960's but if softened after bending it should last for a very long time, way longer than the crappy clear plastic that goes yellow and hard in a month
I don't like clear lines as a ' permanent' fitting, just something else to worry about if you see bubbles in line
The only real issue with copper lines, they may pick up too much engine heat and 'boil' fuel before it gets to carb?
 
I highly doubt you would worry about that kind of heat to boil the fuel. Unless your are running the lines in between the air foils you should be fine. The thinness of the tubing will act just like a radiator and cool pretty fast. On another note, when the injector lines on my shrimp boat engines start rusting out I replace them with stainless steel tubing, just use a regular tube bender for that size tune and your good to go. Have lasted for years on old V8 diesels..

Sent from my Galaxy Nexus using Tapatalk 2
 
We use it (copper) on rod engines fairly frequently, the National Street Rod Association should still have tech on how to use it correctly, since it passes their safety inspections... I know I have a couple rolls of circa 1962 3/8 and 1/2 inch stuff, supposed to be some 1/4 left in the shop somewhere.

You can buy Monel (Cu/Ni) brake lines cheaper at any real auto parts store than you can buy it from Summit or Jegs. You only need a short run, 12-18 inches, for a bike.
 
Thanks for all the advise fella! I'll check locally first for Copper/Nickel (NiCopp) tubing in shorter lengths when I get to that point.

For a CB360 is 1/4" tubing the correct size for this engine? Can you feed the carbs TOO much fuel or does line size not really matter?
 
The stock size is 5.5 mm, a little less than 1/4 inch....but the line size doesn't matter as far as volume, just don't be too small...

3/16 is the smallest I would go...
 
You must log in or register to reply here.

DTT Light or Dark

  • DTT Light

    • Spread the Love

    Back
    Top Bottom