Tag-Along Aux Fuel Tank (joe2lmaker)

[Joe2Lmaker]

Did you compensate volume loss attributed to the two bolt shaft tunnel thingies?

Yup,

VOLUME = 1.1085929e+03 INCH^3

(4.796 gallons)

Without the baffles: 4.853 gallons

Without the counter-bore bungs: 4.912 gallons

 

[dcarver]

Well, today a forced lay off day for me. May as well get outta da house and go riding.. in the name of science, of course!

 

[RadioHowie]

Gheyest picture EVER!!! :finger:

Hey SkooterG was in hood and offered up his hand! It IS Friday, right?

:rofl:

 

[Joe2Lmaker]

O.K. I just weighed the water it took to fill the tank. (It's already drained and drying Hal )

The tank holds 39.90 pounds of water.

Somebody check my math, but 39.90/8.34=4.784gallons

We could convert pounds to kilograms and multiply by the SG of water. Would the answer change?

Plus, there is probably a slight amount of air trapped where the back sheet overlaps the boxed-in section of the bottom.

The CAD model is about 4.8 gallons, weighing the water needed to fill the tank seems to confirm that.

At this point, I'm not comfortable increasing the volume of the tanks being built.

 

[eeksnake]

Seems like an awful lot of variables to rule out or compensate for...

• Angle of tanks during filling (tank on bike/bike on sidestand versus tank on table).
• Accounting for possible voids (shaking the tank during filling).
• Elevation differences (Fridley, MN @ 860' while Creston, CA @ 2000').
• Temp differences (ambient & liquid).

Then again, we're basing this on a guy who paints his nail such a heinous color.

 

[dcarver]

Seems like an awful lot of variables to rule out or compensate for...

• Angle of tanks during filling (tank on bike/bike on sidestand versus tank on table).
• Accounting for possible voids (shaking the tank during filling).
• Elevation differences (Fridley, MN @ 860' while Creston, CA @ 2000').
• Temp differences (ambient & liquid).

Then again, we're basing this on a guy who paints his nail such a heinous color.

In order -

1. Bike on center stand
2. I did not shake n' bake the tank, but if there were voids it sure wasn't obvious. And remember I was filling 1 gallon at a time, then dip sticking to measure, so there was lots of settling time.
3. Not sure about elevation differences...
4. Or Temp!

Because of things, I now have, again, a completely bone dry aux tank, will repeat test tomorrow at a different gas station.
This is curiouser and curiouser!

I mean, how hard is it fill a tank that's dry and read the gallons off the dispensing fuel pump? Guess I'll find out mañana!

 

[dcarver]

Another update -

1. I had to remove my trick 1-way valve. It was weeping.
2. I also replaced the Tygon line with regular line. When I proudly showed my tech the aux tank, and line, he said, "Uhh, I really recommend you replace the plastic line. When it gets hot, it swells and causes problems." Sure enough the end at the tank exit valve was already flaring. I had also noticed that some brand new Tygon line fit 'tighter' than my 1 week old line. So the Tygon is gone. Damn, SkooterG was right. :****: Too bad, that stuff is sweet for routing and looking at air bubbles.
3. I bought 10 feet of Gates and Goodyear 1/4" line. The Goodyear bends much tighter than the Gates.
4. The Gates has a smaller ID - I have on barb, off the valve, that's undersized as compared to all other barbs. With the Goodyear hose, it was loosy-goosy. The Gates was a nice tight fit.. oooooh yeahhh.

Ok, I ain't done yet! I can't stand it. I'm off to town - 35 miles RT, to fill that aux tank again. This time, with Pix!

 

[RadioHowie]

Ok, I ain't done yet! I can't stand it. I'm off to town - 35 miles RT, to fill that aux tank again get some "Passion Coral" polish. This time, with Pix!

Er....umm.....we've seen the earlier examples. You don't need to confirm what we're already thinking.

 

[Patriot]

Another update -[*]The Gates has a smaller ID - I have on barb, off the valve, that's undersized as compared to all other barbs. With the Goodyear hose, it was loosy-goosy. The Gates was a nice tight fit.. oooooh yeahhh.

Ok, I ain't done yet! I can't stand it. I'm off to town - 35 miles RT, to fill that aux tank again. This time, with Pix!

well, just one question...

how did Barb get inserted into this conversation

 

[dcarver]

Ok, I ain't done yet! I can't stand it. I'm off to town - 35 miles RT, to fill that aux tank again get some "Passion Coral" polish. This time, with Pix!

Er....umm.....we've seen the earlier examples. You don't need to confirm what we're already thinking.

RadioH? Jealousy does not become you! We ALL know you're more of pink man... :****: :lol:

Another update -[*]The Gates has a smaller ID - I have on barb, off the valve, that's undersized as compared to all other barbs. With the Goodyear hose, it was loosy-goosy. The Gates was a nice tight fit.. oooooh yeahhh.

Ok, I ain't done yet! I can't stand it. I'm off to town - 35 miles RT, to fill that aux tank again. This time, with Pix!

well, just one question...

how did Barb get inserted into this conversation

et tu, Patriot? :lol:

 

[dcarver]

All righty then.. round two of capacity testing.

Nearly empty tank - less than 1/8" at bottom (did not apply SkooterG ******* this time). Rather, had tank off bike, siphoned out then drained out.

Fuel pump at zero!

Aux tank full! (centerstand, level)

BTW - wiggled the bike, no level change.

And the final gallons - very close to last time of 4.335 IIRC? Uhh, what's work out to, 0.05 gal delta between measurements?

Don't know what to think other than -

1. Are you sure they built the tank to your exact specs?
2. Are you sure you're calculating volume on tank *interior* not *exterior walls?
3. Me, I don't know. What I do know is that my tank holds very close to 4.3 gallons. Should I ask for a refund? Or a spare plastic 1/2 gallon tank? I mean, geesh, when I'm running the next Candy Butt Association rally, I need a full 11.1 gallons, damn nab it!! :lol:

It will be curious to see what your tank actually holds, and I'm willing to take measurements of mine based upon your drawings. But not right now, I have weeds to mow!

 

[dcarver]

I think I've figured it out.

It's the cap assembly. It sits down about 1/2" into tank, making that area 'unfillable'. Tanks with a filler neck could fill the entire volume, and my money says that would gain about .5 gallons.

What do you think?

 

[Joe2Lmaker]

That's it.

The JAZ flush mount fill cap doesn't allow you to fill to capacity.

Hhhmmm

Solution? Would you like me to make you a spacer to raise the flush mount cap?

 

[Joe2Lmaker]

Next question:

How will this affect the people who decided they wanted the JAZ 45° filler neck?

Still, capacity is capacity. I can't add volume to these tanks if it means someone is going to be sweating bullets at next year's IBR.

 

[RenoJohn]

My opinion: The 0.50 gallon variance doesn't mean squat. If you're looking at IBR maximimum, your over 90% to the max in rough numbers.

Now, is there going to be a time when you need 15drops of fuel? Sure, but you'll have that regardless of how much fuel you're capable of carrying.

IMO, the advantage of aux fuel is to give you a range where you're not making inconvenient stops for fuel to "top-off" in order to make the next ideal fuel stop.

Example: You're in rally mode and want to get from Battle Mountain Nevada to Alamo Nevada. Along the way, there is relatively available (but expensive) gas in Austin --Uhh, but that is only about 100miles in and nothing sucks more than having to 'Top-Off so early just to make the next gas station.

So, Tonopah seems like a logical gas stop, and the mileage is about right ...Uhhhh, but crap, that is about a 22mile detour off your route ...which will eat time, energy, efficiency and hurt your rally.

Damn.

But with an FJR and and aux tank with between 3.5 and 4.5, you can get to Alamo which has a couple of convenient gas options ...and you didn't have to stop along the way and top off.

This is the advantage of having aux fuel -and IMO a pint or two of gas isn't going to make the difference -better to have a design and functionality that you like.

Oh, and a representative map for the "visual" folks

====

AND, it aint just rally mode where the aux fuel is awesome. recently I was recreational riding and came to this road. Gas was aprox 35miles away, and a detour ...I had already come about 150miles ...because of aux fuel I had no concerns getting to the next gas. and didn't have to take an aprox 70mile detour to get gas.

BTW, my last aux fuel on the FJR was 4.0 gallons ...very rarely would a bit more have helped. When designing the new cel, I went with 4.0 again. IMO it is the ideal amount. IMO if you like the design of this cel, the volume is perfect.

$0.02 from Reno.

...john

 

[dcarver]

That's it.The JAZ flush mount fill cap doesn't allow you to fill to capacity.

Hhhmmm

Solution? Would you like me to make you a spacer to raise the flush mount cap?

Uhh, No, but it's nice of you to ask. I think RenoJohn has hit the nail on the head - .5 gallons or about 18 miles doesn't mean squat to me. Especially since I know now your tank will drain *almost* dry prior to the main tanks reserve blinky light coming on. When I see blinky light, I have 40-50 miles, period.
If I'm 100 miles away at that point, my bad, poor fuel management.

In other words, for a CBA rider, the .5 gallon delta is the difference between refilling every 2.5 months to every 2.68 months, by my calc's! :lol:

RJ - great reply - a home run.

 

[01VFR]

Next question:How will this affect the people who decided they wanted the JAZ 45° filler neck?

Still, capacity is capacity. I can't add volume to these tanks if it means someone is going to be sweating bullets at next year's IBR.

Being the wuss that I am, I can not get my bike on the centerstand easily so I always fill on the sidestand. I expected a portion of the tank to be "unuseable" due to the tank not being flat. The filler neck was so I didn't splosh all over the bike. I think you could actually get more in using the 45 as it sits on top of your tank with a gasket sandwiching the two. The only thing inside the tank will be the split nut ring thingy. When in rally mode, I only put a safe amount in the aux tank anyways whether thats 4.2 or 4.0, it still beats just having 6.61.

I vote to keep the tank at it's current size as I want mine to be IBR safe.

Corey

 

[dcarver]

Next question:How will this affect the people who decided they wanted the JAZ 45° filler neck?

Still, capacity is capacity. I can't add volume to these tanks if it means someone is going to be sweating bullets at next year's IBR.

Being the wuss that I am, I can not get my bike on the centerstand easily so I always fill on the sidestand. I expected a portion of the tank to be "unuseable" due to the tank not being flat. The filler neck was so I didn't splosh all over the bike. I think you could actually get more in using the 45 as it sits on top of your tank with a gasket sandwiching the two. The only thing inside the tank will be the split nut ring thingy. When in rally mode, I only put a safe amount in the aux tank anyways whether thats 4.2 or 4.0, it still beats just having 6.61.

I vote to keep the tank at it's current size as I want mine to be IBR safe.

Corey

Corey, actually, the split ring thingie isn't needed for this tank..

 

[01VFR]

Next question:How will this affect the people who decided they wanted the JAZ 45° filler neck?

Still, capacity is capacity. I can't add volume to these tanks if it means someone is going to be sweating bullets at next year's IBR.

Being the wuss that I am, I can not get my bike on the centerstand easily so I always fill on the sidestand. I expected a portion of the tank to be "unuseable" due to the tank not being flat. The filler neck was so I didn't splosh all over the bike. I think you could actually get more in using the 45 as it sits on top of your tank with a gasket sandwiching the two. The only thing inside the tank will be the split nut ring thingy. When in rally mode, I only put a safe amount in the aux tank anyways whether thats 4.2 or 4.0, it still beats just having 6.61.

I vote to keep the tank at it's current size as I want mine to be IBR safe.

Corey

Corey, actually, the split ring thingie isn't needed for this tank..

It does when you use a 45 degree filler neck....There's no way to get the wrench in or out with it on.

Joe...I was thinking last night, if the threads on the split ring are long enough, A 1/4-3/8 inch spacer ring welded around the top wouldn't be that bad of an idea...How much volume would that actually add?

Corey

 

[Joe2Lmaker]

Corey, actually, the split ring thingie isn't needed for this tank..

It does when you use a 45 degree filler neck....There's no way to get the wrench in or out with it on.

Joe...I was thinking last night, if the threads on the split ring are long enough, A 1/4-3/8 inch spacer ring welded around the top wouldn't be that bad of an idea...How much volume would that actually add?

Corey

Fortunately, everyone who might want the tank's full volume bought a JAZ 45° filler neck. They come with a spit ring that has studs welded to it (actually bolts, I think). I'm pretty sure they will allow all the trapped air out of the tank and the users will be able to use the full capacity.

To you and me .5 gallons might not seem like a big deal, but in terms of dollars per unit volume Don's little discovery was an eye popper.

If the bolts on the split ring are long enough a spacer could added. It wouldn't need to be welded on. JAZ sells gaskets. The only volume it would add would be to the filler neck.

I'm surprised this hasn't been discovered before. The bowl shape on the JAZ flush mount flange intrudes (better word anyone?) down into the tank and creates an air pocket at the top of the tank. Even though the vent would relieve the pressure in the air pocket, no more fuel can be added because the cap mates up with that bowl shape on the flange.