As I was removing my fuel tank I broke off the barb where one of the fuel lines attaches to the tank. Its broken clear back to the weld so I have nothing to which to attach the fuel line.

The other barb on this tank appears to have been replaced by a bolt-in/on unit, which is much more sturdy than the barb that I broke.  I'm assuming that this is the solution for the barb that I broke.

Can anyone tell me where to get one of these bolt-on barbs and tell me anything I need to now about fixing this problem (I've searched around the forum and internet and I can't find any info about any of this)?  Or, if I need to buy a new tank, please break the bad news to me gently (and let me know if you have a tank for sale).  Thanks much!

The aluminium welder you choose should be good at his job, so should the painter because it'll likely need a respray after the heat of welding. There are a lot of variations in the tanks and it helps us to know what year/model bike you're referring to. For example, a pre-'86 tank has tabs at the back where it attaches to the frame. And later model tanks (K11) have downward facing mounts. Try placing the VIN in your signature for easy answers to your queries. As for what type of barbed fitting was used, got any pictures? It might just be easy to replicate that.

My apologies.  New to the forum, still getting the hang of things.  My bike is a 1985 K100RT.  The VIN sticker is a bit worn, can't make out all of the numbers.  Embarrassingly, I don't know where the VIN on the engine is.  Will see if I can figure out how post a picture in a bit.

'85 K100 tanks on eBay are cheap and plentiful, if you need to go that direction. Perhaps it's an easy fix.

Did the change to the fuel tank happen in 85?


Maybe this might help: where is the power supply to the fuel tank connected, is it at the front left of the tank or at the rear on the right?

The engine number is on the side, when you look at the oil sight glass , to the left where it meets the clutch housing there is a flat strip that's vertical and it is stamped on that.

Above the brake pedal, on the frame, you will see some numbers stamped on the frame. The last 5 or 6 digits are what you need. For example on mine the last digits are 22575 which the records show as being K100RT. There is a database of these numbers here.

Best of luck with it too.

Fuel power supply is at the front and it attaches with one bolt in the middle of the tank a the back; I think this is the old style of tank. Thanks for the info on the VIN locations.  I'll look tomorrow and update my footer to include that info.

In the meantime, I tried to reattach the barb with JB Weld.  I saw that a lot of other people have used it with success to fix tank leaks.  I figured that this is is just a colossally bad tank leak.  I'm letting it cure overnight before trying it out.  I was also thinking about coating that repair with fiberglass, heavy on the resin.  I thought that might plug up any pinholes or voids in the JB Weld.  I'm open to comments/warnings/advice on this fix.

Is that the pressure or the return line that you try to fix (front or back line)?

Crazy Frog wrote:Is that the pressure or the return line that you try to fix (front or back line)?

I would guess that it's the pressure line, as it's mentioned that the other one
is a bolt on version.......which obviously is the return check valve.

Could be a very exciting project this......have the fire extinguisher ready.

92KK 84WW Olaf wrote:Did the change to the fuel tank happen in 85?

'85 and earlier tanks have a bracket across the back end which protrudes a bit - the earlier frame is different as well. '86 and later tanks have only the two downward-facing points which set into the rubber grommets with C-clips, then the K11 tank is different again.

I was searching for an appropriate frame for my project and settled on an '89 and tank from a K11.

My RT has the earlier tank, being 08/84, but I had an idea the change happened before end of 84. Mine is held down by the single bolt at the rear of the tank. The LT has the clip arrangement and they two tanks are not interchangeable.

I just couldn't remember when the tank was changed.

I think Inge is right about it being the pressure line (unfortunately). I'm going to borrow a fire extinguisher from work and have it on hand, just in case. Even if my fix works, I think I'm going to probably get a new tank anyway. I'm not sure that I want to be worrying about this every time I ride. Afterall, a main purpose of riding (for me) is to forget my worries for a moment....

And Two Wheels is correct about the tank configuration. My 85 has the bar across the back and attaches with one bolt. The electronics connection is at the front, between the fuel line connections.

I would not be afraid of having it repaired. I had my tank off and found it had been repaired and welded. A new piece welded in with a new spigot on it and it can work fine. If you have the tank drained and stripped and devapourised its not so difficult to do, just wrap it in flame retardant cloth for protection. There is a risk of pinhole leaks and if the tank is good its worth keeping it. A replacement can bring problems too. On an RT/LT the fairing conceals the bottom of the tank so you may well avoid respraying it!!

For those in suspense about my JB Weld repair, I was successful.  I ended up doing JB Weld for the main repair and then coated the whole area, extending beyond the JB Weld with 5 minute epoxy.  The bike started and ran beautifully.  I let it run for about 10 minutes and there was no hint of any problem.  Unfortunately I couldn't road test is as I have a bunch of other things pulled apart.  

And, Inge, thanks for reminding me to be safe about this sort of stuff.  I did in fact take the bike out of my garage, away from the house, and had a fire extinguisher and a charged hose in hand, just in case.

Probably it would be wise for me to make a real (welded) repair or get a new tank.  If anyone reading this thread has an 85 K100 tank they are looking to sell, let me know.  Otherwise I'll have to start looking for someone who can make this sort of precision weld.

Alumiweld welding rods:

http://www.alumiweld.com/

See the videos I posted on the thread below.

https://www.k100-forum.com/t8796-fuel-tank-cleaning

It's an easy repair. You can use a MAPP gas torch. You need to be cautious when welding a gas tank.

The tank needs to be thoroughly cleaned to prevent an explosion.


Also see Alumaloy:

http://www.alumaloy.com/

Thanks all for the replies and thoughts.  I bit the bullet and bought a new (used) tank, though I'll probably try to do he alumiweld repair on the broken one to have a spare, or maybe sell if the repair looks good enough.

New question now:  are there any quick release solutions for the fuel line so that I can install the hose on that aluminum barb and not have to mess with it again?  Or is there something I should coat the barb with before installing the line to make it easier to remove (though I am worried about fouling the injectors with foreign matter)? I've found it quite difficult to get the hose on and off that barb and would like to avoid breaking the barb on the new tank.

My apologies in advance if this is a silly noob question.

A quick release coupling is used on later models:
Male, BMW part # 13 53 7 700 800.
Female, BMW part # 13 31 7 659 120.

Inge K. wrote:A quick release coupling is used on later models:
Male, BMW part # 13 53 7 700 800.
Female, BMW part # 13 31 7 659 120.

 Hi ! Just logged in and read this post; I use the quick release coupling from an online shop: Louis.de
Very happy with them, fine quality... (Not cheap, though...)
I think they ship worldwide; just to be sure you'd have to ask...

Look in here:
Material 'celeron acetal' (pressure max 10BAR), the ones I use:

https://www.louis.de/en/artikel/schnellverschlusskupplung-schwarz-anschluss-8-mm/10007932?list=32048435

In brass also:
https://www.louis.de/en/artikel/quick-release-coupling-brass-8-mm-connection/10007930?list=32048937

(Either way, you'd need 2 sets of them...)

I can say it's a joy to build of my tank; 2 clicks and I'm 'ready for take off'. No more fidling around with those hoseclamps...

Enjoy !

This is how I did mine, but beware of the plastic connectors, I had to replace mine with brass ones after a failure.

https://www.k100-forum.com/t3308-fuel-line-connectors  

Paul.

Might not help, but I found a pair of special pliers called hose removal pliers, down at the local Auto store. They have a funny end that grips the hose and slips between the hose and metal stub and when you squeeze the pliers
they force the hose off with no twisting. I also put quick release joiners in, just rem,ember to do them up properly.

Like this?:

That's the one Inge, you always seem to have a charged up camera at hand. Well done. (I own the worlds oldest
most simple phone without camera or internet. Must be an old dude.)

Don't feel so sad RT.................haven't internet on mine either.

Inge K. wrote:Don't feel so sad RT.................haven't internet on mine either.

Send it over to me. I'm sure I can get it on-line for you without too much problem!
Bill

Imposibble......it haven't any RJ45 connector.

Inge K. wrote:Imposibble......it haven't any RJ45 connector.

I was going to install a DB9!

(USB would be too modern for this camera.)