Jump to content

Relocating Fuel Pump


Recommended Posts

My only conern with piping in by the regulator is the piping getting too long. But it may be a non issue....

True, and I've thought the same. However, another approach would be to mount the regulator remotely. It doesn't have to be attached directly to the tank after all ^_^

 

We'll see. I finally found some of the fittings I needed, but of course I didn't buy enough, and they are closed for the weekend. So my final installation will have to wait until Monday night.

 

However, I did put the bike back together(minus front fairing) and it all seems to run fine for now... no leaks, etc. So I think the basics of the installation are :thumbsup:

 

...keeping fingers crossed though. I'm always a bit nervous right after surgery of this type :rolleyes: ...time and miles will tell.

 

al

Link to comment
Share on other sites

  • Replies 69
  • Created
  • Last Reply

Top Posters In This Topic

I guess the fuelpump is needed to give the FI

an even pressure in the fuel feed.

 

 

*But* an inquiring mind must know: :luigi:

the fuel tank is still well above the injectors -

would it not be possible to get by without

any fuel pump at all?

Link to comment
Share on other sites

I guess the fuelpump is needed to give the FI

an even pressure in the fuel feed.

 

 

*But* an inquiring mind must know:  :luigi:

the fuel tank is still well above the injectors -

would it not be possible to get by without

any fuel pump at all?

 

No, the fueling system on the V11 needs about 46PSI if I remember correctly. Gravity and sea-level air pressure will only produce about 15PSI at best... if I also remember my high-school Earth Sciences :P

 

While carburated systems rely on air-flow and the venturi effect to draw fuel out of the bowls(reservoirs) of the carburetors, a FI system uses injectors which are really nothing more than high-speed gates/spigots that open and let the pre-pressurized fuel escape for a prescribed duration. It's really the opposite of a carburated design.

 

So, the base requirement of Fuel Injection, mechanical or electronic, is that the system be pressurized, and that is always at a higher pressure than the outside atmosphere can provide. So a pump is required.

 

But, even some carburated systems use pumps if the fuel must be pumped "up" to the carb, or if gravity simply can't provide enough flow. This was true on my '89 FJ1200, as with 4 carbs sucking gas, gravity couldn't keep the bowls filled fast enough :lol:

 

And finally, the regulator at the end of the FI loop keeps the pressure... well... regulated ^_^ Otherwise the system wouldn't stay pressurized, or could over-pressurize... both being most undesireable.

 

 

So as an aside, as I was mentioning about making a "balance tube" .. if "tee"-ing off of the regulator tap into the tank, it would have to be hooked to the "low pressure" side of the regulator, otherwise 46PSI of fuel would be sent back up the petcock, into the fuel-pump, and pressure would be inconsistent. So, either a "tee" would have to be mounted between the regulator and tank "rigidly"... or the regulator could be relocated elsewhere, and the hookup to the tank made with a custom hose. I'll investigate that later.

 

al

Link to comment
Share on other sites

OK, well I more-or-less finished the "phase I" version of this modification, but like all things, I've realized a little better way of doing it. So next week I'll be taking it apart again and tweaking the height of the fuel-pump(raising it a bit to let the intake hose clear the shock mount) and starting to build-in the "tee" and hookups for the balance tube from the right side of the tank.

 

I've got another petcock on the way, and as soon as I nail-down the size/thread of the regulator and dream-up a way to remotely mount it, it should be an easy install. We'll see though :rolleyes:

 

But as it stands now, although not perfect, it works just fine.

 

Bottom line, does it solve/stop the "vapor lock" issue?? I have no idea, and probably never will... unless the bike "vapor locks" again. But alas, that is the nature of these intermittent and hard to reproduce problems. If it never happens again, I guess I can hope to think I've reduced the probability, but who knows yet.

 

Here is a current photo, although this photo shows the supply line without the heat-sheilding installed.

 

al

fuel_pump_no_heat_shield.jpg

Link to comment
Share on other sites

Al has to glue the heat resistant ceramic tiles to the fairing first... :D

 

 

...naw, a bug-strike might chip one, and then.... :o

 

Yeah, I was actually thinking about ripping this all out and making a small fuel-cell to fit where the air-box was on top of the spine. :lol: ...isn't that how it always goes? You get a project pretty much finished, and then .... POW... a new idea strikes!

 

Anyway, I thought about it and after staring at the space, realized I'm talking about maybe a quart of fuel. Sure that's 10 extra miles, but I don't think it would be worth the expense and hassle.

 

So I'll be redoing the current installation a bit, as I mentioned raising the fuel-pump to provide a bit more clearance for the supply line and making the new fittings for the "balance tube" part of the project.

 

al

Link to comment
Share on other sites

Hey Al

Sorry to be a bore but i dont think its a good idea to wrap insulation around the pump that will stop the pump from loosing heat out through the casing.Fuel pumps should be out in the breeze or inside the tank where the petrol keeps it cool.If you look at the pic i put on the other[Tenni pump loc]thread you will see that even though the pump is out front as far from the engine as poss it still has a heatshield between it and the engine. B)

Regards Martin

...........................

Tenni 165

old 950 :luigi:

Link to comment
Share on other sites

Hey Al

Sorry to be a bore but i dont think its a good idea to wrap insulation around the pump that will stop the pump from loosing heat out through the casing.Fuel pumps should be out in the breeze or inside the tank where the petrol keeps it cool.If you look at the pic i put on the other[Tenni pump loc]thread you will see that even though the pump is out front as far from the engine as poss it still has a heatshield between it and the engine. B)

Regards Martin

...........................

Tenni 165

old 950 :luigi:

 

 

hrmmm, understood, but then again the stock location for the pump for everyone else except Tennis is right under the spine, within inches of the *hot* left cylinder... a MUCH net positive heat location. And as you notice from the Tenni photo, the pump is also wrapped in about 1/2 inch of rubber. So I don't think the pump radiates any heat "out" in the stock configuration, at least not significantly. What does cool the pump though is the flow of fuel through it. So I don't(hoping anyway) that my new location and wrapping the pump in heat reflective(90% efficiency BTW :thumbsup:) shielding will overly insulate it. I guess we'll see though. I've run it about 100 miles so far with no issues.

 

However, I am sure that having the pump "out front" on the Tenni like the old Centauro, does aid in cooling, and I think this is why it was moved out front on some V11's until the "in tank" pump was introduced in 2003... since we were having the overheating issues with the stock location under the spine.

 

Bottom line, I'm pretty sure the pump is cooled by the flow of fuel, and the source fuel should now be a *lot* cooler with my supply line about 2 inches further from the left head, and wrapped in the same shielding.

 

Here's more info on the problem, and the inspiration for my design:

 

Vapor Lock FAQ

 

al

Link to comment
Share on other sites

The fuel pump on my '02 Champagne LeMans is out front like the Tenni and the fuel line runs from the tank along the left side of the tank to the pump. A portion of the line rests ON the head.

 

 

:lol: ....yeah, just as I mentioned in the thread where I requested a photo of the "out front" location on Tenni's... isn't it funny how the factory can vary so much on these bikes? :rolleyes:

 

But in the end, also as I mentioned, I think MG just decided to move the pump "out front" on all late '02 bikes before the in-tank pump was ready to go for the '03 models, because they were having all these overheating problems with the previous location with the pump between the cylinders.

 

In regard to your fuel supply line "resting on the head"... in my humble opinion, you should take the tank off, and reroute that line such that it is as far away as you can reasonably make it. There are a multitude of places to lace it up to the wiring harnesses, etc. to get it away from the heat... so it amazes me that MG didn't do a better job keeping it clear of heat-sources.

 

When I look at the whole solution, it amazes me that MG didn't think it through any better.... amazes me....

 

al

Link to comment
Share on other sites

  • 3 months later...

..ok, this project should be getting back on track soon with the myriad others as soon as a few parts show up.

 

As I had mentioned back in June-ish, "phase 1" was complete, and the initial mock-ups in the photos above, as well as a few months or riding have shown the design to at least function reliably = no leaks(knock on wood), runs well, etc..

 

Of course, as also pointed out, I have no idea if I have solved the "vapor lock" problem, as the only proof I will ever have will be in the negative if it happens again. So far it hasn't :thumbsup:

 

 

Now, I can soon start "phase 2"... which will be relocating the fuel pressure regulator, and actually creating a "balance-tube" between the left and right sides of the tanks. I have the various fittings, hose, two OEM manual pet-cocks, and finally have an "affordable" pressure regulator that I can mount remotely on the way.

 

I picked it up from Performance Parts Warehouse, and it's their Weber-Redline "billet" 3.5 bar(~51psi) regulator that they sell in combination with the Weber fuel-pumps I referenced in the "our fuel pump" thread.

 

While shopping around for various regulators, I found that especially in regard to aftermarket adjustable units, they were quite pricey, usually over $150. However, this unit was ~$70

 

As I get this project back on-track in the coming month, I'll update the thread with photos and status. This really should be a weekend job at this point... well after the forks, and replacing all "bullet" connectors with APM weather-tites, and installing the dual-plugs, and the new PCIIIusb... :unsure:

 

...never enough time :P

 

al

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×
×
  • Create New...