Re: fuel system-The nightmare continues

[Karl Johnson <karljohnson@xxxxxxx>]

Although you're having problems with the fuel lines, I had problems  
with the vent tubing.

When my '94 R1100RS was about 4 years old (with about 45k on the  
odometer), the fuel overflow tube developed a slight, but constant  
leak. I took the tank off, the filter and sending unit out, and found  
the rubber tubing was stiff and had developed cracks around the ends  
around the clamps.

At that time I decided to "externalize" the fuel filter following  
Lentini's instructions. I also swapped out the RS fuel filler neck for  
an RT to make topping off the tank easier. FYI...here's the original  
RS filler and the shorter-necked RT model...
http://colorado-artist.com/bmw/images/bmwfiller04.jpg

I checked with my BMW dealership for replacement vent tubing and  
clamps. The replacement tubing was much thicker walled than the  
original tubes. Here's the pic showing the replacement tubing on the  
left and two of the original tubes on the right...
http://colorado-artist.com/bmw/images/bmwFilter06.jpg

The new vent tubing wasn't cut to exact length, there was plenty to  
work with.

For clamps I found some small ones with three prongs which, at first  
seemed like they'd work and would be easier to use than the BMW  
clamps. However, I found I could pull the tubing off of the nipple  
with the alternate clamps where as the BMW clamps wouldn't allow the  
tubing to slip off at all. Here's the BMW clamp and the alternate on  
the right...
http://colorado-artist.com/bmw/images/bmwFilter04.jpg

Although these weren't pressurized lines, I decided to use the BMW  
clamps although I wasn't sure what I'd use to close them. After a  
little trial and error at the auto parts store, I found this tool, a  
CV Boot Joint Plier #25326 for $5. It worked reasonably well...
http://colorado-artist.com/bmw/images/bmwFilter02.jpg
http://colorado-artist.com/bmw/images/bmwFilter03.jpg

For the conversion of the fuel lines I used 5/16" fuel injection hose.  
No problems with or hint of any leaks from the connections to a  
Deutsch FF401 filter.

Anyway, the fuel filer is certainly much simpler to replace and ten  
years later, no leaks from the vent tubes or fuel hoses.

Karl

On Sep 22, 2008, at 10:17 PM, Clive Liddell wrote:

> Hi Will,
>
> No. there is no regulating device in the filter for the Oilheads.
>
> I placed the filter outside the tank on my RT a couple of years back  
> and
> have never looked at the connections since...    Really, 3 Bars is  
> fairly
> high but its not an "uncontrollable" pressure!
>
> A couple of thoughts:
>
> You may have chosen the fuel hose a size too big, and if so it will  
> leak.
> Did you have to push on the hose with a little bit of "force" which  
> would
> have been correct? (5/16" or US-7.9mm is good)
>
> The fuel pump incorporates an over pressure relief and I am not sure  
> of the
> "relief" pressure but it can't be more than say ~4 Bar (just a WAG).
>
> Have you made sure that you have not "switched" the hoses where they  
> go onto
> the FP regulator or, worse, that a hose has become "kinked" where it  
> takes a
> sharp turn?
>
> I avoided sharp turns in the hose by just lengthening the hose from  
> the pump
> back and up over the air filter area and that it where my filter  
> is.  From
> the filter output I loop the hose down and towards the front on the  
> LH side
> of the bike, through the space behind the alternator and then  
> straight onto
> the FPR.
>
> Good luck
>
> Regards
> Clive Liddell
> Pietermaritzburg
> South Africa
> R850R
> R1100RT