Wasted Fuel - Right Side of V11 Sport/LeMans Tank

[mik]

Well, if Guzzi lists the reserve as 1.5 gallons on the 03 model, then my low fuel light came on at the prescribed time. The big question is, I guess, whether the reserve fuel is available for engine consumption. My mileage was around the 120 mile mark. I really don't want to purposely run this thing out of gas or even let the fuel run low in the tank. I just know it's not good for submerged fuel pumps. I.5 gallons is an ample reserve, but it may be that way to provide adequate cover for the fuel pump to provide cooling. I just won't let it run low...when the light comes on, it is time to stop. The reserve is just that..for emergencies like forgetting to stop at the last gas station. The fuel injection on this banger is not as frugal as that on my Daytona. The low fuel indicator comes on and leaves me a gallon in reserve on the Triumph. The Guzzi is what it is.

[Kiwi Dave]

My low fuel light doesn't come on until approximately 230 kM (>140 miles), and I run out a fraction over 330 kM (> 200 miles). Tested the latter more times than I care to admit!

 

So I'm keen to extract that remaining fuel out of the tank, and I'm grateful for Al's pioneering work.

[belfastguzzi]

Thanks Al and all. This reassures that I was probably experiencing fuel starvation, although the warning light had not yet come on.

 

As a matter of interest, my handbook (v11 Le Mans / Sport) gives the tank capacity as 23L (5.06 imp. gall, 6.07US gall) with 5L reserve.

 

The MG brochure for the Scura gives the capacity as 22L. It's negligible, only a litre difference, but it's interesting that MG does not have a consistent spec. for this.

 

My light also comes on around 110 to 120 miles. This is the same as my 600 Ducati that had a smaller tank. I know the Guzzi has a bigger engine, but I had imagined it would have a bigger range than this. I haven't tried to work out a miles per gallon figure yet.

[al_roethlisberger]

Yeah, pretty funny on the various specs eh?

 

My fuel fittings from Summit came in today, so I'll be draining the tank and hooking it all up this evening. I'll then run the tank down to the local gas station for a more accurate fill-up from bone dry.

 

So at least for a 2002 V11 Sport/LeMans, we can know for sure what the normal gross capacity is. I'm hoping that with my mods, the net capacity(what one can really use) will be much closer now.

 

 

In regard to range.... I don't think the V11 is too bad. For me, any bike that can get 180-200 miles from a tank is fine. My friend's '98 VFR can push almost 300 on a good day on the super-slab, but that's pretty extreme. And as we've mentioned, I don't mind stopping every 150 or so miles to stretch the legs.

 

My concern though is when range falls below 150 miles, especially for long tours out in BFE And with the "wasted fuel" issue, I was concerned that the tank didn't give me much insurance past the 120 mile mark when the fuel light lit.

 

In comparison, my very thirsty FJ1200(various performance mods made it no fuel economy champ ) read empty at about 160 miles, but still had a good 40-50 miles left under ideal conditions.

 

But on a positive note, on one of my longer multi-day trips, I got around 43mpg with the LeMans, and saw very good range with the bike... approaching 190 miles before I got nervous. So, with this mod, if all goes well, I think I'll be very satisfied with the range of the bike, and the extra "insurance" the mod will provide.

 

Keep in mind, if the low fuel light glows bright, I'll still probably stop. I'm not trying to maximize distance between fill-ups, just keep them reasonable... 150-180 miles.

 

I'm thinking this is very do-able, even with our tank

 

al

[Murray]

The tank was expanded slightly in 2002/3. Moving the pump and regulartor would of chewed up a little capacity. Who knowes the specs might even be acurate!

[Guest IanJ]

I just had a huge brainwave that might help you (and all of us) out, Al:

 

Why not make the internal fuel return hose longer, and have it pump returned fuel into the left side of the tank?

 

(Actually, in thinking about it, the reason MG didn't do that in the first place is probably because they don't want to stir up water and crud that may be resting at the base of the left side of the tank. Still, that doesn't disqualify it from being a user mod in conjunction with a good solid fuel filter.)

[al_roethlisberger]

The tank was expanded slightly in 2002/3. Moving the pump and regulartor would of chewed up a little capacity. Who knowes the specs might even be acurate! 

 

Hrmm, I do know that technically the tank got a bit larger because of the removal of the "chin pad", but I'd really like someone like Mike Stewart who has both models to measure both tanks to know for sure (..or perhaps you have, which would be great! Results please )

 

It's not that I doubt your report, but the info from MG is sooo sketchy, that at this point I tend to want some purely objective quantitative volume and dimensional data on the tank differences.

 

This could realy matter if one wanted to change over from a 2002 and earlier tank, to a newer tank.... as a physically larger tank might require a new fairing, which means a lot more expense. As I mentioned, I do know that MG shortened the fairing a bit as of 2003, to provide more leg room, and less bashed knees ...but have no idea if the width or height of the tank changed, as I don't think it's possible that the length could have much. There just isn't much room, without changing the frame.

 

This would be a great bit of data to verify and publish, 2002 and earlier gross capacity/dimensions versus 2003+ tanks, and also to know how the in-tank pumps addresses access to that "wasted" fuel, if at all

 

Perhaps someone with both tanks can check this out for us one day.

 

al

[al_roethlisberger]

I just had a huge brainwave that might help you (and all of us) out, Al:

 

Why not make the internal fuel return hose longer, and have it pump returned fuel into the left side of the tank?

 

Sorry Ian, thanks for the suggestion, and it's been mentioned before..... but this won't quite work... a bit... but not to the extent that I was looking for.

 

A couple issues. First, there is no internal "return hose" to make longer. The fuel-pressure regulator just dumps into the right side via a flush hole in the tank. Since it is under some degree of pressure/velocity as it exits the regulator, trying to affix a hose would prove problematic. However it could be done with a bit of ingenuity if one could affix a hose to the outlet of the regulator, but it might be dicey.

 

But more importantly, dumping some or even all of the fuel into the left side still wouldn't solve the problem. It might be an improvement for sure, but still would leave fuel isolated in the right side initially.

 

Think about it... even if there were no outlet on the right hand side as opposed to the fuel return dumping into the right, when the tank was filled initially, fuel would still be "trapped" in that right "saddlebag" once the fuel level was low enough. The only time that fuel might get back over to the left is if via the "slosh" method mentioned before. I will agree that with your suggested method, as long as one didn't "slosh" the fuel back over to the right, at least one of my concerns regarding recirculating fuel dumping right back into the isolated right side would be alleviated

 

This is why we need an outlet or balance tube connecting the two isolated halves... which become isolated once the tank is about 2/3 empty. Regardless of where the fuel dumps, right or left(although right makes it worse to some degree) the end result is the same.

 

But that being said, your suggestion is not without merit It could make for a slightly less "automatically" effective solution, but would still create a real "reserve" that one could have by simply "sloshing" it over... a bit more manual, but workable for sure

 

Again, the trick at that point would be to affix a tube to the regulator outlet that is durable, and to be able to get such a "bent" tube into the little hole while reattaching the regulator

 

Maybe someone can come up with this alternative as a simpler and less drastic modification, to get at least part of the benefits of my more extreme surgery?

 

al

[Kiwi Dave]

Why not make the internal fuel return hose longer, and have it pump returned fuel into the left side of the tank.

 

This was my suggestion way back October last year. My theory was that once the LHS ran out of fuel, then by leaning the bike over you could slosh the trapped fuel from the RHS over to where it could be accessed. Sorta a poor man's reserve.

 

Unfortunately, it stayed at that -theory only. You have to admire Al, who gets up and does something. I'm starting to get that guilty feeling ......

[mik]

I asked a Guzzi mechanic about fuel getting trapped in the tank. His reply was that in the fuel injected models the fuel pump, whether submerged or external has ample power to create a swirling action inside the fuel tank. That is why if the anti-tip valve isn't removed the suction inside the tank caused by the fuel pump makes it hard to get the filler cap open and sometimes causes the paint on the tanks and the tanks themselves to crack...from the vacuum created by the pump. In his words, the fuel is literally forced towards the pickup by the power of the pump.. a mini tornado in the tank. Works for me.

[emry]

Tornado or not, I don't think that fuel exiting the regulator has enough velocity to blast itself over to the left hand side of the tank. It might fountin up a bit and be real pretty in the tank though.

[al_roethlisberger]

I asked a Guzzi mechanic about fuel getting trapped in the tank. His reply was that in the fuel injected models the fuel pump, whether submerged or external has ample power to create a swirling action inside the fuel tank.

 

[snip]

 

In his words, the fuel is literally forced towards the pickup by the power of the pump.. a mini tornado in the tank. Works for me.

 

hrmm, gosh Mik, I don't mean to insult anyone's intelligence with my reply... honestly , but I think the "Guzzi Mechanic" was drinking a little too much of the company kool-aid

 

Seriously

 

 

He either is completely clueless, or didn't understand the question. I'm hoping it's the latter

 

If one looks into the V11 Tank, it's quite obvious that no degree of "swirling" will get the fuel from the right side over to the left once the fuel level has dropped low enough to "isolate" the fuel in the right hand side, the cavity is just too deep... and the fuel return is down at the very bottom of that crevasse I have to wonder if this fella has ever really looked into one ...or maybe he was thinking of an EV type tank(if they are much different in execution)? I hope so, because I'd hate to think he was that clueless.

 

If this "vortex" theory was correct, we wouldn't have to "slosh" the fuel back over by slinging the bike to the left

 

Maybe there's something to this for the in-tank pump models *shrug*, but for the previous, it sounds like he's not even taking the pressure regulator into account, which siginificantly slows the fuel flow from the pump, regardless of how powerful it is

 

 

That is why if the anti-tip valve isn't removed the suction inside the tank caused by the fuel pump makes it hard to get the filler cap open and sometimes causes the paint on the tanks and the tanks themselves to crack...from the vacuum created by the pump.

 

...this other issue mentioned, tank suck, which has nothing to do with the issue we'be been discussing *shrug* .... is indeed caused by the pump in combination with inadequate venting of the tank via stuck tip-over valves exacerbated by the vapor recovery system sucking on the tank as well. Indeed the fuel-pump is the culprit, but not the cause. I don't know where he was going with this one... maybe just an aside?

 

Anyway, regardless, this sounds like typical Guzzi subterfuge

 

Apologies if that was a bit brusque

 

al

[mik]

How much fuel exactly, can be pulled from the tank and used by the engine? I really don't care as long as there is some reserve for me to rely on. I just ride these things and leave the physics of propulsion up to the engineers who designed them. As far as what the mechanics say, or know, that's their business, not mine. After all...I are just an igorant plumer...yoo no..poo goes down, water goes up and payday was today . They are certified to work on these machines and they do it well..at least those I know do. I wouldn't think of hacking on my machine unless it were totally necessary...if it works, then it ain't broke. Since I don't have a degree in automotive engineering, I personally wouldn't guess at the solution to a non-problem, that is why I asked a fellow who fixes Guzzi, BMW, Triumph, Ducati...well you get the point. They do fix them so they must know something. There are a lot of good things to be found here, but there is little doubt that there also exisits some closemindedness....criticism of ideas is an indicator. Sorry about that.

[mik]

Allright.....assuming the mechanics were partaking of a little hooch or blow, or whatever and disregarding the 'tempest in a tea pot' story. Why not just ask MG what the heck they had in mind with their fuel tanks? I do know that fuel systems are touchy...electric fuel pumps..both external and submerged are expensive and I think that they do operate differently. I myself would be more worried about fuel starvation than extracting every last drop from the tank. Was it an oversight by the Guzzi design team to leave fuel trapped in the tank? Beats me...why not askTHEM.

I do know from personal experience that starving the internal electric fuel pumps of gas means no cooling or lubrication and leads to a shorter life and possible engine damage due to low fuel flow. It would be nice to know the answer(s), but as long as the machine runs as intended it seems they knew what they were doing. As for me, when I see the little yellow light, I'm going to start looking for a gas station...I'd rather be riding than wrenching

[al_roethlisberger]

How much fuel exactly, can be pulled from the tank and used by the engine? I really don't care as long as there is some reserve for me to rely on. I just ride these things and leave the physics of propulsion up to the engineers who designed them. As far as what the mechanics say, or know, that's their business, not mine. After all...I are just an igorant plumer...yoo no..poo goes down, water goes up and payday was today . They are certified to work on these machines and they do it well..at least those I know do. I wouldn't think of hacking on my machine unless it were totally necessary...if it works, then it ain't broke. Since I don't have a degree in automotive engineering, I personally wouldn't guess at the solution to a non-problem, that is why I asked a fellow who fixes Guzzi, BMW, Triumph, Ducati...well you get the point. They do fix them so they must know something. There are a lot of good things to be found here, but there is little doubt that there also exisits some closemindedness....criticism of ideas is an indicator. Sorry about that.

 

 

...you are absolutely correct ....as I have pointed out in several threads... that much of what I do "to" my poor bike isn't necessary, and probably creates a good 80% of my "problems" Some of it is pure experimentation, for the simple reason that I think it is entertaining to tinker, or in a few cases it is to address a real problem

 

But yes, "if it ain't broke, don't fix it" if you'd rather not

 

 

As I counseled Dave Gross when he asked about further mods, I said that if one is satisfied with the performance of the bike, then don't tinker... just ride This is especially true if one is not of the tinkering "persuasion"

 

 

But as I offered an "apology in advance" when I wrote my response... apologies again if my response came across as a criticism. I really don't think I'm closed minded, but in these cases I just wanted to "nip in the bud" a couple suggestions that had already been discussed so we don't revisit them ad-nauseum, or in the case of the Guzzi mechanic quickly clarify that... sorry... but I think he's either been misinformed, misunderstood the question, or just pulled this out of thin air As I said before, I hope it's not the latter

 

But as I also offered, it IS possible that his experience was describing another type of tank, such as an EFI Guzzi cruiser bike, or maybe the 2003+ in-tank pump bikes... who knows

 

 

Anyway, unfortunately my and others' actual riding experience with the 2002 and earlier bikes that do not have the in-tank pump seem to contradict the mechanic's description of how the fuel behaves in the tank When my fuel light comes on, and once the bike sputters... I can "yank" the bike to the left and slosh fuel over, and it will run again for a bit... just not long enough.

 

In this case, I think I am not just tinkering for pure fun though, as with the stock setup on a 2002 and earlier bike, 120 miles is where the idiot light comes on, and it's a guess about the remaining fuel.

 

As you mention, I too just want enough fuel/range for reasonably long tours, such as on Hwy 50, "The Lonliest Highway", so that I don't run out of gas... like I almost did in nowhere Utah

 

In this case, I am trying to maximize the utility of the fuel I happen to already be carrying, at least to about 150 miles till "reserve" lights. Otherwise, it's a shame, especially if one get's inconvenienced by limping a bike home, that one can't get to all the fuel already there.

 

And BTW, I'm not impugning all Guzzi mechanics.... as many as certainly quite good, but we've seen more than a fair share espoused here, to find out later that the dealer/mechanic was completely off-base. So I take a dealer/mechanic's explanation/recommendation with a grain of salt. Sorry, but personal experience hasn't done anything but reinforce this position for me And of course, you're welcome to take mine with one large chunk as well I'm not always right.

 

But in this one case, I'm pretty sure I am mostly right.... just because I've been spending a lot of time on the issue, and others have confirmed my observations about the "trapped" fuel. I don't know what else to say.

 

Sorry if I came across as anything but objectively/constructively critical

 

al