Fuel tank removal

[Guest jerroldt]

Can someone please direct me to the thread on fuel tank removal. I want to grease the under-tank electrical connections and eventually change the fuel filter.

In addition, I just want to see what is underneathe tank. I have done some searches but can't seem to find the tread that I saw earlier on tank removal.

[al_roethlisberger]

Well, there may be a thread in "How To", but I don't recall.

 

However, it's so easy, a whole thread is really unecessary

 

For 2002 and earlier bikes:

 

1) Close petcock on left side under tank by rotating clockwise

2) Loosen and remove clamp on fuel supply line on the petcock, and remove line

3) Loosen and remove clamp on fuel return/pressure-regulator on right side, and remove line

4) Loosen and remove single bolt at rear of tank. The tank can now be lifted in the rear.

5) Lift tank enough to see under tank and unhook the electric fuel level sender on left, directly in front of the petcock.

6) Also, you should be able to reach up under the tank and unhook the overflow and vent lines from their nipples, which are about 2/3 of the way up under the tank toward the nose.

 

7) Now lower the tank back down, and grasp the tank at the nose from above(fingers down in the slot the frame passes through) and at the rear where the bolt goes.... and lift up and smoothly to the rear. With the airbox still in place, you may have to slightly lift the rear more than the front.

 

 

The same procedure is used for the 2003+ tanks with the internal fuel-pump, with a few exceptions.

 

On the 2003+ tank, all the connections are on the right side. You simply need to unplug the electrical connector for the fuel-pump module, and disconnect the quick-connects for the EFI loop.

 

I hope that helps!

 

That's it

 

al

[Admin Jaap]

Well, it turned into a "how to..." thread, so that's where I moved it.

[Guest jerroldt]

Thanks for the detailed instructions. I am going to print them out. Jerry

[belfastguzzi]

When things drop, that you are not expecting, they can get lost.

 

So as you haven't done this before, a very small addition is to watch out for the big 'penny' washers when you take the bolt out at the rear of the tank. They are liable to fall when you lift the tank. If you have a nice clean, tidy garage to work in, that won't matter – but just in case...

 

As well as the electrical connections, I grease that bolt and the washers to keep long term corrosion at bay. You might as well, while you are at it.

[pShenk]

I know it's been a long time since the last post on this thread, but this seems like the best place to ask this...

 

Just tonight, I went to adjust the preload in the rear, and ended up removing the fuel tank. It was one of those things where I started wondering "can I unhook this"? and then "what about this?". Before I knew it, the tank was off.

 

Now on my bike (03 v11 sport), there is a fuel line connection on both the right and the left side of the tank (right and left when I'm sitting on the bike). On the left looks like the main petcock, the line going into what I assume is the fuel pump. It has a knurled knob that closes it off (still dribbles a little when the line is disconnected, but mostly off).

 

Out of the fuel pump, the gas line goes into the left injector, and then over to the right injector. The line then goes out of the right injector, and up back into the tank on the right side.

 

On the right, this line connects to what looks like another petcock. Instead of a gnurled knob, like on the left side, there is a small rod sticking out of it, to enable it to turn. I thought that it was to open or close the valve, but after I removed the line, it didn't look like turning it did anything. No fuel came out, although it was wet with gas.

 

Any clue what this thing on the rear right of the tank is? Is it some kind of fuel return valve? How does it work... is it open/closed by turning it 90 degrees? I rotated it around several times and it didn't seem to be unscrewing, so I left it back in the original-pointing position (towards the front of the bike). I'm not sure if I rotated it back as many times as I rotated it out though.

[Guest ratchethack]

It's the fuel pressure regulator. The open tube coming out of it at 90 degrees is the ambient air pressure reference. Regulators are designed to work off of a negative manifold pressure reference. I've experimented to see if there might be any benefit in connecting this to the intake manifold via the canister-hose barbs in the manifolds, but it didn't make a single solitary bit of difference.

[pShenk]

Ok, thanks. What does it do (obviously regulates pressure). It varies the fuel pressure based on the difference between the ambient air pressure, and the relative vacuum in the manifold?

 

Im having trouble picturing exactly how it works...

[Guest ratchethack]

Ok, thanks. What does it do (obviously regulates pressure). It varies the fuel pressure based on the difference between the ambient air pressure, and the relative vacuum in the manifold?

 

Im having trouble picturing exactly how it works... 

Pshenk, I think you're missing something here. Lemme take a stab at this.....

 

I've never taken one apart, but by the way it works, I would deduce that it's simply a coil spring acting on a diaphragm that opens and closes a valve with fuel flowing through it. The valve position varies directly with the difference in pressure between the fuel line and the pressure of whatever you connect to the "reference".

 

In the case of the OEM V11 Guzzi setup, the reference is ambient, so a predetermined fuel pressure is maintained independent of the throttle. In many other applications (such as on cars), where the reference is connected to the intake manifold, fuel pressure is allowed to increase by the regulator as a response to decreased vacuum in the manifold, which occurs when the throttle is opened. The effect is to give the injectors more pressure when they need it for more optimal fuel delivery when the throttle is open.

 

In the case of the OEM V11 Guzzi, the regulator seems to be calibrated so that the injectors get ample pressure under open throttle and the injectors deliver enough fuel under all throttle conditions.

 

If I were drag racing or chasing a land speed record, I'd probably have a whopping high fuel pressure requirement to feed an engine built for maximum output at WOT. But speaking for myself, (for Road Geez purposes, that is - and for the purposes of y'er average rider, riding around on low throttle openings 99% of the time) I reckon the OEM setup is more'n satisfactory.....

 

Hope this makes sense?

[pShenk]

thanks Ratchethack, that helps a lot! So the regulator maintains an even fuel pressure (relative to the ambient air pressure). I suppose that that pressure would be the maximum that the injectors need at any given point in the map. I'm sure the injectors have some device for modifying the amount of fuel sent into the cylinders... is that just time that they are open? Or can they vary the rate that the fuel flows?

 

Sorry I might be asking basic questions, but I figure this is a pretty good place to ask

[Guest ratchethack]

Hey, no prob Pshenk. I think I can answer this one just fine - but if we're going any further into fuel injection and/or mapping, I'm gonna hafta defer to somebody else. There seem to be a few deep-techie bit-twiddlers around with lots of ECU expertise, and I ain't one of 'em....

 

You're correct - The amount of gas that goes into the fuel charge is determined solely by the pulse width of the signal from the ECU. The pulse width is determined by the programmed fuel map, throttle setting, and I think RPM too, though now I'm (thankfully! ) completely out of my area of understanding......

 

Y'see, I've got a PC III with an "off the shelf" map. Thankfully (Part II), my bike has run flawlessly ever since I put it in, gets great mileage -- and I've got NO NEED WHATSOEVER to start messin' with perfection......

[dlaing]

I suppose that that pressure would be the maximum that the injectors need at any given point in the map.

90516[/snapback]

Not exactly.

The fuel pressure is supposed to be the constant and specific pressure that the injectors need at any given point in the map.

The pressure should be sufficient enough to meet the maximum needs of the injectors.

Oddly, the shop manual says, "Note that to keep the pressure jump to the injectors constant, the difference between the fuel pressure and the intake manifold pressure must be constant"

But then they show a photo of it clearly not connected to the intake manifold

The pressure adjuster is preset to 3 bars, plus or minus 0.2bar.

PS Ratchet's definition of "perfection" is clearly that of a relativist See "ECU" thread for more details on the pursuit of perfection, and see "global warming" thread for details on relativism

Or maybe he meant to say,

"-- and I've got NO NEED WHATSOEVER to start messin' with the FI system to achieve perfection...... wub.gif"

[Guest ratchethack]

There seem to be a few deep-techie bit-twiddlers around with lots of ECU expertise, and I ain't one of 'em....

Pshenk, I might have added that some of the above-mentioned (ahem) will consider a bike that delivers smooth, clean, crisp acceleration, pulls hard and clean at every RPM, has plugs that read a perfect pale-tan color, and consistently gets 35 mpg with "spirited riding" to be mapped ALL WRONG unless and until it has been dyno-tuned and/or custom-mapped so that the stoichiometric ratio reads "correctly" at WOT at every RPM according to a graph on a piece of paper - even though most riders (including me) seldom hit WOT, and when they do, it's generally only for a few seconds every couple of hundred miles or so....

 

There are several kinds of digital programming devices that are marketed to make your Guzzi run "The way it SHOULD run". These devices, which connect to your bike's ECU, historically seem to consume literally months of dedicated time and effort at the keyboard and on ECU threads, require many pages upon pages of technical reading and controversial discussion and argument with the experts on technical Forums, demand nearly endless perusing of voluminous data tables, etc., - all seemingly accompanied by ratty running and bad mileage, mind you! - whereby a more "technical" flavor of perfection is eventually arrived upon that is then judged "acceptable" - often, evidently despite persistent bad running and/or worse mileage......[sigh]......

 

Oh - lest I forget - the expense of the programming device itself and that of the multiple dyno pulls required to justify the use of the device in the first place can fairly easily reach upwards of a thou$and......

 

Call me a Luddite, but somehow I seem to have missed the sheer joy of all of this while I was out riding what, at least by any "off paper" standards, would have to be considered a brilliantly tuned Guzzi....

 

Matter of fact, I've had nearly a dozen prior bikes (still got one) with carburetors, (a primitive fuel mixing device that once flourished in an age prior to the wonders of digital control) which, though they were (and still are) tuned (by me) to my version of "perfection", no doubt ALL had INCORRECT stoichiometric ratios all up and down the power band! Was it a Good Thing there was no way of even knowing that this was ALL WRONG at the time??..... Thinking back on it, it's a wonder I ever managed to survive all those thousands of miles and still consider it real life......

 

But by all means leave me not steer anyone away from the "freedom" of modern technology -- and to each his own........

 

BAA, TJM, & YMMV

[dlaing]

Stoichimetric perfection on a Guzzi is not desireable on a Guzzi as the engine would run too hot.

Perfection in ECU tuning is impossible, and excellence in ECU tuning is really rather subjective.

Excellence could be defined as maximized power for every map point.

Or it could be defined as being a little leaner than that for cleaner emissions and MPG.

Or it could be defined as being a little richer than that for cool smooth running.

Or it could be defined as being a bit richer in some places, to keep it cool, while being a bit leaner in other places for efficiency, while being optimized for power in other places, all while balancing ignition timing with fuel mixture.

Or it could be defined as a flat lambda reading from a Tuning Link dyno run.

Or it could be defined as a state of tune tha leaves the rider perfectly satisfied

[Guest ratchethack]

Ratchet's definition of "perfection" is clearly that of a relativist

Dave! You seem to've taken considerable exception to my idea of "perfection". And yet:

Excellence could be defined . . . as a state of tune tha leaves the rider perfectly satisfied

I find the amazing relationship between the above two statements, each in context used, to be yet another demonstration of the Relativist mind at work........

 

But then, as a lifelong dedicated Absolutist, much of life itself is always chocker-block full of such amazement and wonder.......