Fuel Tank mod, fuel pump stuff & my measured fuel tank/reserve capacity

[stevepsd]

Since I needed to drain the fuel from the tank to do the O-ring recall/check (mine was ok, btw) I decided to check the actual fuel capacity of my tank. I rode around until the low fuel segment started flashing and got home in 2.5 miles from it coming on. I siphoned the remaining fuel out of the tank and measured 180 oz of fuel remaining. based upon the design of the fuel tank/pump it looks that all but about 4oz-6oz is useable. So to be conservative, say 1.25 US Gallons (160 oz) of reserve capacity.

I then measured how much fuel it took to fully fill the tank. Mine was 6.125 US gallons (784 oz). Pretty darn close the 6.08 gallon capacity listed in the owners manual.

I also took the opportunity to take a look at the fuel pump. The pump is modular, and real easy to disassemble. There was some debris in the fuel pickup filter (as shown in the pics).

Since I always hated the filler neck restrictor (it was a pain to fill - kept spitting fuel back at me, fuel nozzle at a awkward angle, etc) I decided to cut it out. Real simple mod using a air die grinder with a abrasive cutoff wheel (after letting the tank air out for a couple of days - don't want any boom!). Since the restrictor is just over 1 inch in height (depth), it does free up some tank capacity. My tank now holds 6.35 US gallons (813 oz) almost another quart. Plus it is much easier to fill and no splash-back!

Washed the tank out real good and the fuel pump opening makes it pretty easy to reach inside and wipe down the tank. It helps if you have long, skinny arms also. You definitely don't want to get you arm stuck in there though....it really diminishes your tank capacity if you have to hack it off!


29 DEC 2011 UPDATE:

After running the tank dry, there was 9 ounces of fuel remaining.

To itemize for my stock (unmodified) tank:

TOTAL USEABLE CAPACITY (unmodified tank): 6.05 US Gallons

TOTAL MAIN TANK CAPACITY (prior to reserve): 4.72 US Gallons

RESERVE CAPACITY (useable): 1.33 US Gallons


After modifying the tank by cutting out the restrictor:

TOTAL USEABLE CAPACITY (modified tank): 6.28 US Gallons

TOTAL MAIN TANK CAPACITY (modified tank - prior to reserve): 4.95 US Gallons

RESERVE CAPACITY (useable): 1.33 US Gallons

 

[dcstrom]

I also took the opportunity to take a look at the fuel pump. The pump is modular, and real easy to disassemble. There was some debris in the fuel pickup filter (as shown in the pics).

Good to know - just to confirm... the fuel filter is easy to get to, and replaceable (and hopefully cheap)? That would be good... I'm used to the drama with V-Strom pumps. The filter is replaceable, but it's (incredibly) a $200 part. The entire pump is $600! I did the filter bypass mod and now run an external $3 filter.

Trevor

 

[Tremor38]

Interesting mod. Can't say I'll be doing it anytime soon, but maybe something to file away for later. Thanks.

 

[stevepsd]

Trevor,

The inlet filter is not removable. It is crimped in place by a small steel band. It can only be cleaned by back-flushing if you disassemble the pump. It draws fuel from both sides of the element. It's about 1" x 2" in size.

However there is a very large filter on the outlet of the pump. It is molded into the outer body of the fuel pump housing. It is about 2" x 4" in size and around .375" thick. You can just see a bit of it in the last pic - the filter element, from what I could see, is very convoluted in its design - so lots of surface area for it's compact size.

Neither of these filters, or any parts of the fuel pump are available separately. It is only sold as a complete unit.

A place in China is selling this pump for $140. It has the right part # on the pump. Don't know if it is a copy or not. http://www.ebay.com/itm/250923185376?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

 

[markjenn]

I siphoned the remaining fuel out of the tank and measured 180 oz of fuel remaining. based upon the design of the fuel tank/pump it looks that all but about 4oz-6oz is useable. So to be conservative, say 1.25 US Gallons (160 oz) of reserve capacity.....I then measured how much fuel it took to fully fill the tank. Mine was 6.125 US gallons (784 oz). Pretty darn close the 6.08 gallon capacity listed in the owners manual.

Interesting, but I'm not see how all these odd steps and assumptions add up to an accurate measure of usable fuel.

I think we've had three people now run the bike until it quits and then only be able to get about 5.7-5.8 into it (with the stock restrictor). I'd put my trust in this number.

- Mark

 

[stevepsd]

Based upon where the fuel pump inlet is, and where it is positioned in the tank (tank mounted on the bike - bike on the centerstand), I poured fuel into the empty tank and directly observed how much fuel it took to cover the fuel pump inlet filter. It was right around 4-6 oz. I don't have the exact number since I poured in 6oz first and it covered the filter & a bit more.

It is easy to directly observe this when the restrictor is removed from the filler neck.

It is possible that the draw of the fuel into the fuel pump causes some swirling/sloshing around the inlet and at low fuel levels air could be introduced that could interrupt fuel flow. This I did not check. That is why I am using a conservative reserve capacity of 1.25 gallons (160oz) instead of the 180oz that I actually removed from my tank (I rode the bike 2.5 miles back home after the fuel gauge started flashing). Don't forget this is measured in MY TANK, with MY FUEL SENDER. Yours is probably different.

And I don't understand your 'odd steps' comment. How else would you easily measure fuel tank capacity other than pouring in measured fuel into a empty tank until it is full?

Believe what you want.

 

[Tremor38]

And I don't understand your 'odd steps' comment.

.....Naw, I won't go into it. I will throw out the word 'predictable' though.

 

[3putt]

Makes you wonder sometime if he even has a S10. Nice report Stevepsd.

 

[colorider]

Nice report Steve! I'm still planning to use an awl to punch a hole or two in my filler neck.

 

[jajpko]

.....Naw, I won't go into it. I will throw out the word 'predictable' though.

::025:: ::025::

 

[stevepsd]

Nice report Steve! I'm still planning to use an awl to punch a hole or two in my filler neck.

You know I was going to do this as well, but after taking a bit to ponder I decided that since I had to pull the tank anyway to check the o-ring, it was not that much more effort to cut the darn thing out. It took literally 2 minutes. Done. Gone. Good Riddance!

 

[stevepsd]

Makes you wonder sometime if he even has a S10. Nice report Stevepsd.

::026::

Some wish to contribute in a positive way, others seem hell-bent on wanting to tear it apart.

 

[tc9988]

Interesting, but I'm not see how all these odd steps and assumptions add up to an accurate measure of usable fuel.

I think we've had three people now run the bike until it quits and then only be able to get about 5.7-5.8 into it (with the stock restrictor). I'd put my trust in this number.

- Mark

Actually quite the opposite. Full means different things to different people. Some think when the pump shits off its full, some think up to the bottom or almost up to the bottom of the restrictor is full, while others will go slow and wiggle the bike to remove trapped air and call that full. Here we have a reasonably precise measurement done on a tank that started completely empty and has the restrictor removed. The measurement is consistent with Yamaha's published values. The others were not.

Thanks Steve. I will travel with confidence that I have at least 6 gallons of useable fuel provided it is full at least up to the bottom of the restrictor. I will punch holes in the restrictor

 

[stevepsd]

Elwood,

Actually, being the somewhat anal engineer that I am, I measured the tank capacity both before the restrictor was removed and after I cut it out. The tank was completely drained prior to each measurement and the tank was bolted to the bike as usual. No weird angles or anything. The shop floor is within .1 degrees of perfectly level (at least this spot anyway).

With the restrictor in place, the tank was filled until the fuel was at the very bottom of the restrictor (and just started to spill into the bottom opening of the restrictor). My tank measured 6.125 US gallons or 784 ounces exactly. This is with the bike upright, on the centerstand.

With the restrictor removed, I filled the tank to the just below the brim (a 1/4" or so) to allow room for the cap to close. This was 6.35 US gallons (813 ounces). Bike was in the same spot in the shop as before, upright, on the centerstand.

I am going to mostly drain the tank and run it until the bike stops and see how much unusable fuel in left in the tank. It might be more than the 6oz that is needed to cover the fuel inlet filter.

-steve

 

[markjenn]

And I don't understand your 'odd steps' comment. How else would you easily measure fuel tank capacity other than pouring in measured fuel into a empty tank until it is full?
Believe what you want.

What I am saying is that the obvious approach of running the bike until it quits on the side of the road, then measuring how much fuel you can get into it is the definitive measure of how much useable fuel capacity the bike has. It is not subject to any measurement errors or assumptions about what the reserve capacity is. Three people that I'm aware of have done this and all are reporting 5.7-5.8 gallons until the fuel is at the bottom of the filler neck which is where Yamaha says to stop filling the bike (and after which it is relatively difficult to continue burping the bike with more fuel.)

It is possible there is variations between samples, but I doubt there is 0.35 gallon variation. If you have time, it would be very interesting for you to perform this test on your bike. I plan on doing this for mine but haven't had the time.

You're absolutely right - believe what you want.

- Mark

 

[Don in Lodi]

Ah, there it is; Capacity and Usable Capacity.

 

[stevepsd]

I just did a engine running test and ran the bike out of fuel, twice. The bike stopped with 9 ounces of fuel left in it. So that is 3 ounces more than what it takes to cover the fuel inlet filter sock (which is not much fuel level wise....looks like less than 1/4".

Since I am a bit of a OCD engineer (EE but really a frustrated ME) at times (or so my wife says anyway - I think I'm fine ) I ran the test twice. Once with it running at idle while sitting on the centerstand and another while running around the neighborhood 25-55mph. I did not stray to far since I really don't want to have to push this beast very far. Wanted to see if change in fuel demand has any effect.

In both cases I emptied the tank and put back in 16 oz. Ran it still it stopped. Then siphoned out every drop (on centerstand and side-stand to get everything I could). When done I cannot see or hear any fuel sloshing around. I got out 9 ounces and maybe .25oz more when it was just running on the centerstand.

So this is the data for MY bike. MY tank.

Yours might be different. How so? Well, if the intake filter sock is slightly lower or higher it will change when the pump can no longer draw fuel. That's one way. I noticed that there is almost no gap between the bottom of my intake filter sock and the fuel pump housing. There is also some 'slop' in all of the plastic fuel pump housings that click together. They are not very precise. This could affect the distance between the bottom of the tank and the pump intake. Another is if you are pointed uphill or down which will change how the fuel column level is in relation to the intake.

==================================================

So to reiterate, for MY bike, MY tank, MY fuel sender, MY fuel gauge:

MY stock, unmodified tank holds 6.125 US gallons (784 ounces) when filled to the bottom of the fuel restrictor (fuel just coming thru the holes) when on the centerstand.

My low fuel light came on with 1.40 US gallons (180 ounces) of fuel remaining in the tank (this is while riding on flat & level). Out of that, 9 ounces is unusable, leaving a useable reserve of 1.33 US gallons (171 ounces). On MY BIKE.

MY modified tank (sans restrictor) holds 6.35 US gallons (813 oz) when filled to within 1/4" to the bottom of the brim of the tank.

P.S. The fuel measurements were all done using a 32oz/1000ml chemistry beaker (dual marked in ounces) - thanks to my bud in the Chemistry Dept at work.

I think my work here is done.

-steve

 

[GrahamD]

So to reiterate, for MY bike, MY tank, MY fuel sender, MY fuel gauge:

-steve

It's OK Steve, No one is going to sue.

Thanks for doing all that to YOUR bike. I am sure that it will be within a few percent for anyone else.

By the way was that measured at standard temperature and pressure? ::025::

I mean you never know what might happen if the tank is cold. Could be pushing it a couple more metres with a shrunk tank.

Funny, when I think back to my first bike, all I remember being "thingy" about was adjusting the points and checking the oil and keeping it clean.

I can't remember who I sold it to, how much fuel it took, how many Km it had on it. Fuel economy, Whether the spokes were all the same tension. Nothing.

Just rode it and filled it up when needed. I am sure that's what most of my friends did too. Same with the next bike.

Now I'm getting thingy about more stuff.

What has happened to us?

 

[Don in Lodi]

Thingy...thingie? Thingiephobia? ::010::

 

[tc9988]

Because I had nothing better to do I went back to see if I could find some of the posters who thought the tank held 5.8 gallons +/-.

October 6 Elizilla Well, I drove about 15 miles in between bringing gas to the bike in a gas can, and filling it up again. The gas can brought me 1.77 gallons, and the fill-up was a further 4.37 gallons. I filled it on the sidestand, and the level was just over the little plate with the holes in the filler neck. Based on my average mileage, the 15 miles I rode probably used 0.3 to 0.4 gallon. So from full up to empty is about 5.8 gallons.

Maybe there's another 0.4 gallons in there, but if so it doesn't get fed out very easily. Note that I did not try leaning the bike to one side or the other to funnel the remaining fuel to the pump. It may be possible to do that. I know that on my V-Strom I once got the bike to travel another three miles to the next gas station, by stopping twice and tilting the bike way over to the left. I don't know what side the outlet is on, in the Super10, since I haven't had the tank off yet.


Oct 03 madddog 5150 On the way home today I decided to see how far I could push my luck. I did not run out, but this was as much gas as I have ever put in the tank. Here are the details:

Miles on tank: 255
Calculated MPG: 44.44
Displayed MPG: 46.8
Gallons Pumped: 5.738


Twisties Sept 03 Well, ran it dry. One cough a few hundred feet early. Pulled off, was idling normal. Accelerated to 35. Stopped for red light. Died while at idle. Added two 20 oz cans of fuel (MSR bottles) = .313 US Gallons (G). Started right up, and I mean right up. Was a gas station within 75 feet. Pulled in and filled to the bottom of the filler neck insert on side stand. Took 5.290 G. Total is then 5.60 G usable capacity.

Obviously you might squeeze a bit more in there if you were planning on riding before it could expand, but for general use as designed I think we have 6.08 G tanks of which .48 is expansion capacity and 5.6 is nominal usable capacity.

Notice a pattern here. Filling up on the side stand, not running out of gas. To date Steve is the only one I'm aware of that has used a methodology that could produce repeatable results. Its more than just coincidence his testing yields a capacity the same as published by Yamaha. Does anyone really think Yamaha would pull the same bs BMW did when they misrepresented the useable 1150GS fuel tank capacity.

I'm an engineer and I'll stick with the Steve's results. Everybody else can of course believe what they want.