Anyone understand siphons and/or where to get non-return valves that
will tolerate petrol?

Situation: petrol tank for my bike is shaped like an inverted 'U'.
Very clever in that the fuel pump is in one side of the U and there is
no connection between the bottom of the two halves.

Solution: construct a self-priming and self-purging siphon that sucks
fuel from the isolated half of the tank into the pumped side. Such a
thing was made by an American chap according to a US bulletin board that
I came across. It seemed to be, basically 'Y' shaped with non-return
valves at the top ends of the valve and some sort of non-return
purge-valve in the tail of the Y. The whole thing goes upside down into
the tank with the purge valve at the highest point.

Unfortunately the designer dissapeared from the BB some years ago and
I've not had any success posting questions on the subject.

TIA

Richard

On Tue, 04 Jul 2006 22:38:40 +0100, Richard wrote:

Anyone understand siphons and/or where to get non-return valves that
will tolerate petrol?

'e
http://www.lauche-maas.com/suche_seite2/52870ED51136a14126wyQk1E39B8/hst/staL/haupt/vollr%C3%BCttelpumpe/mr1/sr0/grp.html

It's a) in German, b) a stainless steel non-return valve, c) 19 Euro. The theory
is: You stick into on the end of a tube, dip the end with the valve in the tank,
shake it up and down to prime the siphon and get the siphon started.

Don't know it'll work for you, but it is an non-return valve that will tolerate
petrol...



Thomas Prufer

"Richard" wrote in message
...
Anyone understand siphons and/or where to get non-return valves that
will tolerate petrol?

Situation: petrol tank for my bike is shaped like an inverted 'U'.
Very clever in that the fuel pump is in one side of the U and there
is
no connection between the bottom of the two halves.

Solution: construct a self-priming and self-purging siphon that
sucks
fuel from the isolated half of the tank into the pumped side. Such
a
thing was made by an American chap according to a US bulletin board
that
I came across. It seemed to be, basically 'Y' shaped with non-return
valves at the top ends of the valve and some sort of non-return
purge-valve in the tail of the Y. The whole thing goes upside down
into
the tank with the purge valve at the highest point.

Unfortunately the designer dissapeared from the BB some years ago
and
I've not had any success posting questions on the subject.

TIA

Richard

OK my motorcycle knowledge is somewhat dated, but every tank I've been
associated with 'hung' over the top frame rail, and had two outlet
taps which fed pipes that came together in a 'Y'. This way you always
had a 'reserve tank' when the level got down to the situation you are
describing.

AWEM

Richard wrote:
Anyone understand siphons and/or where to get non-return valves that
will tolerate petrol?

Situation: petrol tank for my bike is shaped like an inverted 'U'.
Very clever in that the fuel pump is in one side of the U and there is
no connection between the bottom of the two halves.

I assume that is sarcasm. Are you sure? Why would the designers be so
stupid as to fit a tank that can never be fully utilised?

MBQ

wrote:
Richard wrote:
Anyone understand siphons and/or where to get non-return valves that
will tolerate petrol?

Situation: petrol tank for my bike is shaped like an inverted 'U'.
Very clever in that the fuel pump is in one side of the U and there is
no connection between the bottom of the two halves.

I assume that is sarcasm. Are you sure? Why would the designers be so
stupid as to fit a tank that can never be fully utilised?

MBQ

Well as you go round corners I expect it sloshes a bit anyway..

Or has an internal coupling between the two..

wrote in
oups.com:


But no guarantee where it ends up.


Or has an internal coupling between the two..

That's what I suspect, or external as another poster implied,. The OP
implies there's no connection and he is trying to fix the stupid
design.

Maybe not, it all depends on the dimensions. My bike taps inlet ends used
to be set up a bit from the bottom of the tank to help avoiding crud
entering. If the cutout for the to tube ends up being quite shallow at the
back end, then sloshing around plus the height of the petrol tap feed may
make all practicable use of the petrol.

mike

wrote in :

My bike taps inlet ends
used to be set up a bit from the bottom of the tank to help avoiding
crud entering. If the cutout for the to tube ends up being quite
shallow at the back end, then sloshing around plus the height of the
petrol tap feed may make all practicable use of the petrol.

I'm sure I had one at one time where the (one) tap had a main and
reserve setting, with the main coming from an upstand into the tank.


You certainly did - they were dead common.

The tap has two concentric inlets at two levels; when the higher inlet runs
out, you change the tap to "reserve", and it allows perol to enter the
lower inlet.

Al you had to do was remember which way to turn the tap when it happens
when you're halfway through overtaking a juggernaut

mike

On Tue, 04 Jul 2006 22:38:40 +0100, Richard wrote:

Situation: petrol tank for my bike is shaped like an inverted 'U'.
Very clever in that the fuel pump is in one side of the U and there is
no connection between the bottom of the two halves.

Simply link both sides with a U pipe. No valves or taps needed. Provided
the pipe is big enough, then flow through this link pipe will drain both
sides equally, leaving you with a trivially small undrainable volume
that's merely the contents of the pipe.

But motorbikes generally tap both sides anyway, and have a changeover
tap. This gives you a reserve available only by switching over which is
the volume of one isolated side. Cleverly this reserve is also
"automatic" and you'll still have a reserve next time, even if you
forget to switch it back when you fill up.

Andrew Mawson wrote:
"Richard" wrote in message


OK my motorcycle knowledge is somewhat dated, but every tank I've been
associated with 'hung' over the top frame rail, and had two outlet
taps which fed pipes that came together in a 'Y'. This way you always
had a 'reserve tank' when the level got down to the situation you are
describing.

AWEM



Yep, all my previous bikes with saddle tanks were thus equipped. Not so
the products from BMW or, at least, in the case of my R1150GS

Richard

wrote:

Richard wrote:

Anyone understand siphons and/or where to get non-return valves that
will tolerate petrol?

Situation: petrol tank for my bike is shaped like an inverted 'U'.
Very clever in that the fuel pump is in one side of the U and there is
no connection between the bottom of the two halves.


I assume that is sarcasm. Are you sure? Why would the designers be so
stupid as to fit a tank that can never be fully utilised?

MBQ

Totally sarcasm free. You might care to examine the next R1150GS you
get close to.

Richard

The Natural Philosopher wrote:

wrote:

Richard wrote:

Anyone understand siphons and/or where to get non-return valves that
will tolerate petrol?

Situation: petrol tank for my bike is shaped like an inverted 'U'.
Very clever in that the fuel pump is in one side of the U and there is
no connection between the bottom of the two halves.


I assume that is sarcasm. Are you sure? Why would the designers be so
stupid as to fit a tank that can never be fully utilised?

MBQ

Well as you go round corners I expect it sloshes a bit anyway..

A bit

Or has an internal coupling between the two..

None. Hence the siphon solution. The desparate out-of-petrol solution
is to lean the bike over towards the pump half.

Richard

wrote:



The OP
implies there's no connection and he is trying to fix the stupid
design.

Yep. It's a BMW.

Richard

wrote:

I'm sure I had one at one time where the (one) tap had a main and reserve
setting, with the main coming from an upstand into the tank.


Yep. On bikes with external fuel pumps or simply gravity fed carbs.
Not so on my FI BMW.

Richard

wrote:



My BMW petrol tank is lik two saddle backs over the propshaft. I guess
that the action of filling up the right hand side primes an internal
pipe to the left hand side, then as the right hand side goes down the
fuel flows from the life through this pipe. Or not.

Which BMW? My R1150GS has no link

Andy Dingley wrote:

On Tue, 04 Jul 2006 22:38:40 +0100, Richard wrote:


Situation: petrol tank for my bike is shaped like an inverted 'U'.
Very clever in that the fuel pump is in one side of the U and there is
no connection between the bottom of the two halves.


Simply link both sides with a U pipe. No valves or taps needed. Provided
the pipe is big enough, then flow through this link pipe will drain both
sides equally, leaving you with a trivially small undrainable volume
that's merely the contents of the pipe.

I'll try it. But how will the fuel be drawn from the side without the
pump over the top of the inverted 'U' into the side from which the fuel
is pumped?


But motorbikes generally tap both sides anyway, and have a changeover
tap.

Not where there is an in-tank pump.

TA

Richard

The message
from Richard contains these words:

Yep, all my previous bikes with saddle tanks were thus equipped. Not so
the products from BMW or, at least, in the case of my R1150GS

Sometimes the top tube slopes enough so that at the nuts end of the tank
there's no bridge for the fuel to cross. My DT125 and CX500 were like
that.

--
Skipweasel
Pay no attention to that man behind the curtain.

On Wed, 05 Jul 2006 22:21:43 +0100, Richard wrote:

I'll try it. But how will the fuel be drawn from the side without the
pump over the top of the inverted 'U' into the side from which the fuel
is pumped?

It won't - use a U pipe, not an inverted U.

Richard wrote:
wrote:



My BMW petrol tank is lik two saddle BAGS over the propshaft. I guess
that the action of filling up the right hand side primes an internal
pipe to the left hand side, then as the right hand side goes down the
fuel flows from the life through this pipe. Or not.

Which BMW? My R1150GS has no link


oops. I should have made that clearer - 740i - i.e a car :-)

Richard wrote in :


None. Hence the siphon solution. The desparate out-of-petrol solution
is to lean the bike over towards the pump half.

I thought that was an excellent feature - when you were out of main and
reserve, there was a bit left you could find

mike

In message . com,
writes

Richard wrote:
wrote:



My BMW petrol tank is lik two saddle BAGS over the propshaft. I guess
that the action of filling up the right hand side primes an internal
pipe to the left hand side, then as the right hand side goes down the
fuel flows from the life through this pipe. Or not.

Which BMW? My R1150GS has no link


oops. I should have made that clearer - 740i - i.e a car :-)

So why doesn't every other BMV owner have the same problem ?

--
geoff

raden wrote:


So why doesn't every other BMV owner have the same problem ?



AIUI, like me, they simply mutter about poor tank range. I manage about
165 miles from £15 or 15.5L of fuel. The fuel gauge reads off the same
lobe as contains the pump. It's not an enourmous amount of fuel that is
trapped in the LHS, just enough to make it worthwhile building a siphon.

Richard

Andy Dingley wrote:


It won't - use a U pipe, not an inverted U.

Sorry, don't follow that. How do I fit this into a tank shaped like an
inverted U?

On Fri, 07 Jul 2006 20:34:09 +0100, Richard wrote:

It won't - use a U pipe, not an inverted U.

Sorry, don't follow that. How do I fit this into a tank shaped like an
inverted U?

Fit it underneath. This is also where you have access to get to the pipe
fittings (unless you fancy working through the filler cap with
tweezers).

Andy Dingley wrote:


Fit it underneath. This is also where you have access to get to the pipe
fittings (unless you fancy working through the filler cap with
tweezers).

Hi Andy

On the inner face of the right hand lobe is an *enourmous* access plate
for pump and in-tank fuel filter. Some day soon I must replace that
filter as 24,000 miles is fast approaching. I thought that I could
combine both jobs.

Richard

wrote:
Richard wrote:

Anyone understand siphons and/or where to get non-return valves that
will tolerate petrol?

Situation: petrol tank for my bike is shaped like an inverted 'U'.
Very clever in that the fuel pump is in one side of the U and there is
no connection between the bottom of the two halves.


I assume that is sarcasm. Are you sure? Why would the designers be so
stupid as to fit a tank that can never be fully utilised?

MBQ

The R1150GS Adventure (successor to the R1150GS) has a cross-over tube
between the lobes, as has the Touratech fuel tank.

In message , Richard
writes
raden wrote:


So why doesn't every other BMV owner have the same problem ?



AIUI, like me, they simply mutter about poor tank range. I manage
about 165 miles from £15 or 15.5L of fuel. The fuel gauge reads off the
same lobe as contains the pump. It's not an enourmous amount of fuel
that is trapped in the LHS, just enough to make it worthwhile building
a siphon.

I'd better check my Haynes BOL

--
geoff

Richard wrote in :


AIUI, like me, they simply mutter about poor tank range. I manage about
165 miles from £15 or 15.5L of fuel.

I'd stop muttering - I get 125 miles (remarkably consistently) from my Suzy
SV650.

The fuel gauge reads off the same
lobe as contains the pump.

Do you have a reserve? I get a warning at 12.5l used, I guesstimate 35
miles left, but I don't push me luck

mike