1948 UL fuel tank cross over fuel line

Fuel Leak?

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Eb74UL
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1948 UL fuel tank cross over fuel line

#1

Post by Eb74UL »

So I bought reproduction fuel tanks and crossover solid line. The tip of the fuel outlet nipple of the right hand side fuel tank is kinda square like, not like the tip of an oil line fitting but really like a square butt.

Now, the tip of the solid crossover fuel line that hooks to that right tank output nipple looks like the end of a brake line. Given that, I would have expected the nipple of the gas tank to look more like the inside of a brake caliper inlet, with some kind of a cone shape tip... but it is not, it is really square or flat if you prefer.

I think there is no way that this is not going to leak. Should I post pictures? or have you guys seen this and what is the take on this?

I tried to put a picture but was not able to upload, don't know how to do it... tried the "insert image" icon above the text but did not figure it out...
Andygears
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Re: 1948 UL fuel tank cross over fuel line

#2

Post by Andygears »

The repop parts don’t fit together, imagine that! Are they from the same vendor? V-twin perhaps? The nipple should look like a miniature oil tank fitting but may have been replaced if the tanks are not new. You need to post a picture, search the site. And determine what size and threads the tank has. If it is a replaced fitting and pipe thread, you might find an adapter fitting that would work, otherwise welding in a new correct fitting is probably inevitable.

Andygears
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Re: 1948 UL fuel tank cross over fuel line

#3

Post by RUBONE »

There are two different type fittings on original tanks, one is internal and flat ended for pre 1940 tanks, the other has a standard nipple with a conical end from 1940 all the way to 1965. A picture of what you have will help but it sounds like aftermarket parts being wrong.
Eb74UL
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Re: 1948 UL fuel tank cross over fuel line

#4

Post by Eb74UL »

RUBONE: I think you nailed it. This is exactly my problem and since you point out that some tank nipple have a conical end, it means I have the wrong combination of tank and fuel line. I will get a conical tip machined to be inserted in the tank nipple that I have, that should solve the problem. Sorry I can't figure out how to post pic. Would you know the angle of the cone that I need to make?

Andygears: The Solid fuel line that I have screws into my the tank nipple perfectly, the issue is strictly the shape of the tip of the nipple, looking at the fuel line, it is obvious that the nipple tip should be conical. I am happy to find out that there is such a a thing as a flat end nipple because that would really be a mess if it had not existed and I had gotten a hold of that.

Now to clarify all this, it is very important for me to state this: This issue is of my own making. The problem is that I am trying to use 1948 reproduction parts to use on a shovel frame. I thought I would order as many 1948 parts in case one day I'd go to a rigid. When I tried to use the 1948 solid line, it would not be possible to hook it up when bolting the tanks into a shovelhead frame, so I bought a fuel line for a panhead. I actually had to buy a few solid line to find one that would work. While I found one that would work on the length and shape, with some bending of course, now it does not work on the tank nipple tip shape... Nobody told me it would be easy I just thought so myself!

On another note, to avoid the line cracking I was thinking of heating it to a red glow in the middle once installed. I know I will loose some of the zinc coating but I'd rather loose that than get the line to crack. I do have it to a point that the stress is really low on the line but I though heating would definitely eliminate all stress.

Thanks for the replies, now I know what I have to do.

Would anyone know the conical angle to use?

Eb
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Re: 1948 UL fuel tank cross over fuel line

#5

Post by RUBONE »

Actually that external threaded flat ended nipple is not like any fitting ever used by H-D. Total screw up on the part of the tank maker.
Eb74UL
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Re: 1948 UL fuel tank cross over fuel line

#6

Post by Eb74UL »

Thanks RUBONE, now I am pissed off! Repops that don't fit... once again!

In case some people wonder why I am putting a UL motor on a shovel frame... I just bought it that way!

Eb
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Re: 1948 UL fuel tank cross over fuel line

#7

Post by Andygears »

If the tank nipple is pipe thread, straight or tapered, why not just get a hose barb nipple and use hose for the crossover? Easy way out when it’s a non original setup.

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Eb74UL
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Re: 1948 UL fuel tank cross over fuel line

#8

Post by Eb74UL »

Andy, the nipple is not pipe thread, it is regular thread and should have a cone tip just like the inside of a female brake line. The end of the solid line that connects to the tank nipple looks just like the double flared end of solid brake line. The reason I want to use a solid fuel line is strictly for looks... The bike has solid oil lines as well so I thought it would be nice to use the solid fuel line. I did not expect to run into this kind of issue... considering I ordered parts that should have been compatible. I could not count the number of repop parts that I bought that were wrongly made. I got to the point where I try to buy good used parts on Ebay before anything else. In the case of UL fuel tanks I am pretty sure you understand why I bought repop $$$$$$$
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Re: 1948 UL fuel tank cross over fuel line

#9

Post by Andygears »

OK, if the line threads on the tank but has no “seat” to bear against because it’s too short and it’s flat. Maybe you get someone with a lathe to make a little insert to form a seat inside. Or buy a brass fitting that has the correct cone and cut the cone off, file the cut square, use thread sealer on threads, push the insert into the line and tighten it all.

I would pressure test it before any paint or assembly and hopefully it won’t loosen later. Short of welding the correct fitting into the tank, I don’t know how you get correct appearance otherwise.

Andygears
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Re: 1948 UL fuel tank cross over fuel line

#10

Post by 59Panman »

Eb74UL,

Here is what I did when my tank mount cracked. I can always go back to original easily.

See post #13
Fuel tank nipple
Eb74UL
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Re: 1948 UL fuel tank cross over fuel line

#11

Post by Eb74UL »

50Panman, yes I understand what you did but in my case there is no taper end on the tank nipple at all so I cannot use any kind of "taper" fitting on it, either AN or flared. It would have to be some kind of square ended pipe with a gasket.

I see clearly the taper end of the nipple in the picture on the thread you provided, my tank nipple does not have that taper at all, it's just like that nipple has been machined totally flat instead of taper.

As it is, the only way, other than the one I mentioned above, to connect anything to that nipple would be to hook a rubber hose with a clamp, even though it's a threaded nipple (and we know how fuel likes to travel through the threads even against a clamped rubber hose).

So I am going to take an AN fitting and machine the taper end off of it, leaving a small pipe end to be inserted into the tank nipple hole that I will slightly enlarge prior to the machining. I will then insert this "taper end adapter" (taken off the AN fitting) into the tank nipple hole which will then create a taper end on that currently flat nipple end... I will put some fuel resistant epoxy on the bottom of my insert so that it wont leak...

I did not pay that much attention to that when I received the tanks a few years back and they are painted now so I have to find another way to solve this than welding another bung or returning the tanks...

When I got this bike I though "this is going to be easy, just change the fuel tanks and the oil tank to the old style"... Ah ah ah! How the hell did I even have that thought!

Eb
Last edited by Eb74UL on Wed Jan 12, 2022 7:01 pm, edited 1 time in total.
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Re: 1948 UL fuel tank cross over fuel line

#12

Post by RooDog »

I understand what Andygears is saying, and agree with that plan....

Another thought: Do we know what the thread is on the tank's fitting, diameter & pitch?
....RooDog....
Last edited by RooDog on Wed Jan 12, 2022 7:06 pm, edited 1 time in total.
Eb74UL
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Re: 1948 UL fuel tank cross over fuel line

#13

Post by Eb74UL »

Was in the process of writing my previous post, I have the same idea as Andygears... I'll let you know how it turns out a few month from now, it's snowing here anyway...
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Re: 1948 UL fuel tank cross over fuel line

#14

Post by Lowbikemike »

Can you please post a picture of what you have. It sounds like you have the slip fit type connection that is found on the petcock of later Panheads.
Eb74UL
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Re: 1948 UL fuel tank cross over fuel line

#15

Post by Eb74UL »

I tried to post a picture but have not been able to do it. I read the help section and I was able to upload a picture. It took me a while but I found the picture that I uploaded in a location that seem to be related to my profile. However, I did not find a way to bring this picture into this post...

I saw the possibility to insert a link but I do not use any cloud storage space and honestly, I do not want to use them, I do not need them and cannot get myself to open another space that I'll have to manage, is there anything easy?

So sorry for my stubbornness but unless someone can explain an easy way for me to do this, it wont happen. Yes, posting a pict would have likely saved a thousands words but I think we got it nailed anyway! Thanks to all and I will follow up!

Eb
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