Fuel Return Line Collapsing (UNICOIL)

[Martin]

A few week ago I suffered intermittent bad running, this was due to the fuel return line collapsing where it bends at 90 Deg to enter back into the tank. I tried a few solutions but it eventually collapsed again, the collapse mainly occurred on really hot days in traffic around 39 C.  I tried at least 5 different ways of routing. I removed the fuel cooler which was causing one of the problems due to the fuel line  needing rerouting. I trimmed back the line about 1.5" to do away with the point where it was collapsing. All these measures worked from anywhere from a couple of days to a couple of weeks. I have it cured at the moment with a rather ugly solution. I extended the hose by about 10" with a barb joiner ran the hose up through the steering head and looped it around and back into the tank. All the bends are now large with no possibility of kinking, and the K75s fairing covers it all up. However I went in search of springs to go over or in the fuel hose in order to solve the problem,and make it a little bit neater. A guy I deal with at Pirtek put me onto these Unicoil which are a modern interpretation of the old spring trick. Autobarn has them in various sizes $20.00 Au or Ebay has the identical ones for $8.00 Au plus $8.00 Au postage.  https://www.ebay.com.au/itm/5-16-Stainless-steel-UNICOIL-Hose-coil-suit-hose-OD-14-16mm/152678074659?
When it arrives I'll post the results, although I can't see there being any problems with it at this stage.
Regards Martin.

Unicoil 2.jpg (34.03 kB . 500x375 - viewed 513 times)

[K1300S]

Probably using a piece of straight hose.   Bends are too tight.

Suck it up and buy the oem pre formed hose from bmw. Problem solved.

[Laitch]

Suck it up . . .

Or allow it to suck up—your choice. :giggles

Please update us from Paradise on the efficacy of the unicoil, Martin.

[Martin]

Marshall BMW in OZ only sells fuel hose by the metre. May be able to get one Ex UK $50.00 Au plus freight from Motorworks, however it states this pipe connects to the throttle housing bank. I'm not sure it is the correct one. Motobins only sell by the metre. Given that the Unicoil is reusable I think I might stick with it, even if the molded hose was available. Laitch I'll let you know, it's supposed to arrive on Monday. What do they cost in the US, I know I shouldn't ask.
Regards Martin.

[Martin]

I just checked Ebay USA it's an Ozzie product and it's cheaper in the US even with freight. 
:dunno :dunno :dunno :dunno :dunno :dunno :dunno :dunno :dunno :dunno :dunno :dunno :dunno :dunno :dunno :dunno :dunno :dunno Regards a ripped of Martin.

[Laitch]

I just checked Ebay USA it's an Ozzie product and it's cheaper in the US even with freight. 

Why are Ozians gouging their mates with the product's price? Is it some kind of self-hating syndrome? :giggles  You should open a dialogue with them, Martin.

[Martin]

Laitch the Pirtek guy who told me about the Unicoil told me to try two places to get them. As one place was just around the corner I went there, Autobarn and normally they are not too bad on prices. However since then I have done more research and I could have got them straight from  the actual distributor in SA for $7.55 Au plus freight.  However the freight is $12.00 Au which would give me the substantial saving of $00.45 Au. However if you buy 12 and the freight cost stays the same. So it pays to buy in bulk. With 12 Unicoils imagine the circuitous path that they could take.  :hehehe Unfortunately I can't seem to copy the link to the distributor autopartswholesalers.com.au
Regards Martin.

[K1300S]

Marshall BMW in OZ only sells fuel hose by the metre. May be able to get one Ex UK $50.00 Au plus freight from Motorworks, however it states this pipe connects to the throttle housing bank. I'm not sure it is the correct one. Motobins only sell by the metre. Given that the Unicoil is reusable I think I might stick with it, even if the molded hose was available. Laitch I'll let you know, it's supposed to arrive on Monday. What do they cost in the US, I know I shouldn't ask.
Regards Martin.

you can't order part #13311460857 at the bmw dealer?  preformed return line with two bends.  $20 ish.

[Martin]

Marshall just about everything for a K has to be ordered Ex Germany 4-6 weeks. And if you can get it for $20.00 it will be $50.00 Au. However just for interest sake if BMW rings me tomorrow I'll ask the price and availability. They are chasing a couple of gaskets for me.
Regards Martin.

[woodgeek]

I ordered four 1/2” Gates unicoils from Rockauto for $3.87 each, $2.99 shipping. Part #28510.

[Martin]

Arrrrgh oh well what's done is done. It should arrive hopefully tomorrow. :dunno
Regards Martin.

[The Mighty Gryphon]

I have a return line cracking at the bend on the Moby Brick.  Gonna try a couple of these to eliminate the bend:

https://www.ebay.com/itm/9-49mm-SAE-5-16-8mm-Elbow-90-Degree-Nylon-Fuel-Line-Quick-Connect-Release-Hose/253318287446?hash=item3afaf25056:g:jsIAAOSwI59Z7Mtk

If they look a little too cheesy to trust, I can use one of these guys with two clamps.  Doesn't matter what it looks like since the fairings hide the connection:

https://www.ebay.com/itm/2-pc-5-16-8-mm-HOSE-BARB-ELBOW-90-DEGREE-Brass-Pipe-Fitting-Gas-Fuel-Water/252820092072?hash=item3add4074a8:g:xLQAAOSw32lYzXBN

[K1300S]

I get the poor aussies who get had with shipping, but why all the US folks trying to put all the cheezy parts together to kludge up a solution when you can get the correct BMW part easier and cheaper?

[The Mighty Gryphon]

I haven't checked the return hose for the K75S, but for my K100RS it costs $36.65.  With the only damage being the cracking at the bend I can easily think of a whole lot of other things to spend money on.

[Martin]

Gryph the Pirtek guy actually suggested the 5/16" brass elbow if I couldn't get the Unicoil. When I first started playing with cars internal and external springs were a known solution for tight bends and collapsing hoses. You could get them from speed shops and hardware stores, not these days. :dunno However Uncoil under the Gates banner has all sizes to cover fuel and coolant hoses.
Regards Martin.

[K1300S]

I haven't checked the return hose for the K75S, but for my K100RS it costs $36.65.  With the only damage being the cracking at the bend I can easily think of a whole lot of other things to spend money on.

If one end is cracking, and assuming the whole hose was made at the same time...I would guess the other end should be replaced too.  For only a few bucks more than a bunch of repair parts and your time, you could just replace the whole thing.  Fuel hoses should be replaced as preventative maintenance.

Just a thought.  :-)