Relocating Fuel Pump

[Kiwi Dave]

Oh, and btw as an aside, I think making a cross-over tube would be really easy as well. The petcock and fuel-pressure regulator both are screw-in affairs. All one would have to do is add a "T" fitting(post regulator) and a balance tube.

What's the issue with the remaining fuel in the RHS of the tank? In desperation after running out of fuel, just lie the bike over on its LHS to relocate the trapped fuel to the inlet pipe. For those fastidious types who aren't keen on lying their pride and joy over too far, unbolt the tank and tilt accordingly.

 

Or have I missed somethin'?

[al_roethlisberger]

.... I suppose that could be another "approach"

 

BTW, in all seriousness, "sloshing" the bike right and left does get some fuel over the spine, but not much. One is still left with a goodly amount stuck on the right side of the tank. I wasn't too worried about it, but since I was relocating the pump anyway, I thought... hey, why not

 

al

[guzzi323]

What's the issue with the remaining fuel in the RHS of the tank?  In desperation after running out of fuel, just lie the bike over on its LHS to relocate the trapped fuel to the inlet pipe.  For those fastidious types who aren't keen on lying their pride and joy over too far, unbolt  the tank and tilt accordingly.

 

With regards to what Kiwi Dave said above, wouldn't the excess fuel the regulator returns to the tank almost immediately fill up the right side again as soon as you turn the iginition (and fuel pump) back on? I think you need a way to have the regulator 'dump' excess fuel back on the right.

 

Unless I'm completely missing the point of what Dave's talking about or how the system works.

 

Anyways, it's way too early to for me to be trying to think but that's what my sleep deprived brain came up with.

 

Cheers,

johnk

[twhitaker]

I just raise the front tire about 2 feet from the ground and a goodly portion of the fuel dumps over. I bought 4.8 gallons after 177 miles yesterday.

[dlaing]

So if you are running low on fuel, just keep popping wheelies!

[guzzi323]

So if you are running low on fuel, just keep popping wheelies!

 

That works for me..

[al_roethlisberger]

What's the issue with the remaining fuel in the RHS of the tank?  In desperation after running out of fuel, just lie the bike over on its LHS to relocate the trapped fuel to the inlet pipe.  For those fastidious types who aren't keen on lying their pride and joy over too far, unbolt  the tank and tilt accordingly.

 

With regards to what Kiwi Dave said above, wouldn't the excess fuel the regulator returns to the tank almost immediately fill up the right side again as soon as you turn the iginition (and fuel pump) back on? I think you need a way to have the regulator 'dump' excess fuel back on the right.

 

Unless I'm completely missing the point of what Dave's talking about or how the system works.

 

Anyways, it's way too early to for me to be trying to think but that's what my sleep deprived brain came up with.

 

Cheers,

johnk

 

 

..well, keep in mind that this is something of an experiment, and is only an inspired "secondary" part of the primary goal of the project, which was to relocate the pump and fuel-lines. ... since I was already in there tearing it up

 

To answer your question though.... well it'll be much easier once I have it done and post pictures, but here goes....

 

- Many bikes, especially ones with "saddle bag" type tanks like ours, have "balance tubes" that equalize the fuel level between both sides of the tank. This allows access to more of the fuel, but isn't necessarily 100% effective depening on tank design, location of the taps, etc. But it does help to keep one side from becoming isolated.

 

- We do not have a "balance tube" on our EFI Guzzis

 

- On our EFI Guzzis, the tap/petcock comes out the left side, and the low-pressure return from the fuel pressure regulator(that hat shaped thing under your right tank) dumps into the right as the fuel makes the circuit through the EFI loop

 

- This causes the right side to have to "fill up" before sloshing over to the left side of the tank to get back to the passively(ambient air pressure/gravity) fed petcock and fuel supply on the left

 

- This is obviously less than "efficient"

 

- So,I will remove the OEM fuel pressure regulator, and install an OEM petcock in it's place

 

- I will then install a "remote" regulator and out of the low pressure outlet of the regulator, attach a "tee" so that one leg will go to the right side of the tank, and the other to fuel pump. This will in effect cause the return fuel to balance between both sides of the tank as it exits the EFI fuel circuit. Obviously there will still be some favor to the right side unless I engineer in some sort of % flow control, but that's getting too complicated. This solution should allow fuel to get to the pump more directly(directly from the return, instead of through the tank) and again, allow the fuel to balance in both sides to some degree.

 

 

Again, even if it doesn't work really well, no worries, it's a neat experiment since I was already moving and replumbing the fuel pump and line

 

I'll let you know if it works well or not once I have it all hooked up in a few weeks.

 

al

[Guest JohnInNH]

Now my HD has a tube to connect both tanks. It came out the bottom front of each tank. A small rubber tube connected to each outlet with a small clamp top keep it from leaking.

 

They were very handy to take off and tap off some gas if ya needed some for cleaning parts or if a guy ran out of fuel. Just slip it off and fill a cup/beer can, then transfer it to his tank.

 

If our plastic tanks had a spigot on each it would eliminate the problem. Now, just how to affix one to the bottom of each side!

[al_roethlisberger]

..that's very true, and Rich and talked about this idea about a year ago. The problem however is that we don't have steel tanks(even that might be dicey to drill/tap) and it would be hard to find a good place to locate a tap that would be reliable in the plastic ones we have.

 

I would be concerned about tapping the plastic tank, and attempting to make it heat and vibration proof. I don't like fuel leaks

 

But yes, I wish we had that option... honestly... Perhaps someone could do it, but I thought this would be easier and more reliable. We'll see.

 

al

[Kiwi Dave]

With regards to what Kiwi Dave said above, wouldn't the excess fuel the regulator returns to the tank almost immediately fill up the right side again as soon as you turn the iginition (and fuel pump) back on? I think you need a way to have the regulator 'dump' excess fuel back on the right.

I accept the shortcomings of my earlier thinking.

 

However, not to be beaten (yet), perhaps what is required is an internal pipe on the return feed that favors the LHS of the tank. It would work as normal until the division starts when the tide goes out, at which point the fuel would be returned exclusively to the LHS and available for the supply pipe.

 

If this was successful all the available fuel should be able to be consumed, but my "poor man's" reserve would disappear.

 

I might have a look to see how easy it would be to add the internal pipe next time my tank is off and the fuel is low.

[guzzi323]

However, not to be beaten (yet), perhaps what is required is an internal pipe on the return feed that favors the LHS of the tank. It would work as normal until the division starts when the tide goes out, at which point the fuel would be returned exclusively to the LHS and available for the supply pipe.

 

That was along the lines of what I was thinking as well but I have so many projects going on right now that involve bikes that either don't run or don't run very well that I'm thinking it'll be quite some time before I get around to something like this.

 

If you figure it out, let us know..

 

johnk

[al_roethlisberger]

This is indeed an interesting idea, but even if one had the return line from the fuel pressure regulator on the RHS internally feeding the LHS(where the passive petcock is) as opposed to just dumping into the RHS, there would still be fuel "pooled" and stuck on the RHS from the original filling of the tank, and "sloshing" during a ride that still would have no return path to the LHS.

 

If I understand what you are getting at, the net result is still that one would have ~1/2 gallon of fuel stuck on the RHS of the tank once the fuel level fell below the spine hump

 

From a different perspective, effectively this design is the equivalent of having the petcock and return on the same side of the tank(which I thought about). But the end result is the same. The side of the tank that can not freely flow to and out the petcock will retain the "unobtainable" fuel...

 

If so, then a balance tube of some sort is still required.

 

...unless I am missing something (And I could be )

 

al

[Kiwi Dave]

If I understand what you are getting at, the net result is still that one would have ~1/2 gallon of fuel stuck on the RHS of the tank once the fuel level fell below the spine.

Yes, except that when tilting the tank over you can regain that fuel to the LHS and the recirculating fuel pump will return it to the same side. Some might inevitably be sloshed back over to the right, necessitating further tilts.

 

I only see this as emergency procedure when that gas station you were relying on didn't appear on the horizon, or some other miscalculation.

 

I miss my reserve petcock on the range of Triumphs I rode many moons ago, and the miserable warning light on the Le Mans is too dull and cries wolf far too early. (In my case about 240kM for a range around 300-320kM.)

[al_roethlisberger]

OK, well "stage II" is well on it's way, and hopefully will be complete by this weekend.

 

I've removed the OEM fuel pressure-regulator from the tank, and installed the second manual petcock. And from the photo below one can see that I've installed the new 3.5bar external regulator, and plumbed everything for hookup.

 

I'll clamp everything down and heat-shield it tomorrow, and hopefully it will work as expected.

 

Will this make a big difference? I don't know, perhaps not a great deal in balancing the fuel level. But since I had already relocated the pump to successfully combat the vapor-lock issue, and half the plumbing was already done... why not

 

I'll let ya'll know if it functions acceptably.

 

al

[al_roethlisberger]

Yep, disregard the mess in the photo above ...that was a mock-up, and I came up with a couple different arrangements after this. I think I've got my final setup ready, and I'll post a picture ASAP.

 

This addresses two issues:

 

1) Relocated/Shielded fuel-pump, supply lines, and filter reduce or eliminate the "vapor lock" issues, verified by Gio in his vapor lock thread.

 

2) By creating a "balance tube" this allows balancing both sides of the tank to equilize fuel levels on both sides of the tank, and allow equal(or near equal) syphoning from both sides, where the OEM design isolates a significant amount of fuel on the right side and only allows syphoning from the left.

 

Results from further testing to follow.

 

al