1985 K100RS fuel line

[Lawrence]

With Spring due in my neighborhood next week and the promise of fairer weather, I decided to bring my K100RS out of hibernation.  As I was warming her up a bit in anticipation of the first ride this year I smelled fuel.  I discovered it was puddling around the injectors of the engine  :eek:
Off came the riding gear and I pushed her back into the work area for some probing. Turned out the fuel was leaking at the hose on the fuel tank.  I pulled it off but there was no obvious split or failure of the hose.  In the course of doing this, I peered down the end of the hose and to my great surprise there appeared to be a smaller hose within the hose, about 1 1/2" down from the end of the hose.  This smaller one doesn't look like it would pass over the fuel pipe that exits the tank, but I didn't try since it was too short to reach the pipe. 
I pushed the hose back up on the pipe, tightened the clamp and fixed the leak.  I then had a very chilly ride and it seems to be holding fine. 
However, the hose is a mystery to me.  This was fuel injector fuel hose I purchased last fall from the local NAPA store, and it's rated for something like 150 psi. When I cut it to length and fitted it from the tank to the fuel rail I did not notice any separation of the hose that would explain why it now appears to be a "hose within a hose."
Anyone have an experience like this?  An explanation or cockamamie idea as to why has happened here?

[TimTyler]

Maybe the I.D. of the Napa hose you got was a little small?

[Lawrence]

Thanks for that diagram, Tim.  Now I'm concerned.  It well may be that I'll have to replace all the NAPA hoses.  I do not enjoy wrenching on that bike; there is just too much stuff cramped into a very tight space!  The diagram you posted makes me suspect I've only clamped the "cover" on the hard bits, resulting in a very weak connection on all the lines. 
What I cannot understand is how this escaped me when I bought the  piece of hose and cut it to lengths for installation.
Another thought: with three hoses, one within the other, how would this be pliable enough to slip over the various fittings?

[TimTyler]

I just bought preformed replacement hoses from the dealer. They weren't that expensive and they last a long time.

FYI - That diagram is just from a web search. I don't know that it represents the hose you bought. Check with Napa.

[WoahGold]

I had a similar problem last year. I found a place online that sold parts for old BMW cars. The fuel line on the bike is the same as the line for the 318i and it was cheap by the meter, I replaced all the lines and no problems since.

[Lawrence]

"They weren't that expensive and they last a long time."
Tim, you're a fortunate man!  They sure don't seem inexpensive compared to my budget.  I just ordered the OEM hose in question from the local dealer.  I figure it works out to a price of something in excess of $50 per foot.  I did order it -- through clinched teeth.  Talk about gettin' hosed....

[TimTyler]

It's $22.  Certainly more expensive than bulk hose, but at least you know it'll fit perfectly.

[Lawrence]

apparently BMW has discontinued the preformed fuel hose.  I ordered the piece that goes from the tank to the fuel rail, but what was delivered was one meter of hose... just as if I'd have purchased it at the local auto supply store.

[JamesInCA]

That hose (like the in-tank submerged hose, which is different) they sell by the meter.

The pre-formed one that might matter is the return hose, from the FPR to the tank. It's shaped to fit through the rather narrow route it has to follow back up to the tank: http://www.bmwmcchattanooga.com/products/Hose/1032186/13311461011.html.