LBS Fuel Cell V1.5

[L.B.S.]

I'd like to start off with a heartfelt thanks to Dale (HondaBikePro) for selling me his original fuel cell V1.0

He made it pretty much exactly as how I envisioned making one, long before even buying my NCX back in 2012. Alas, I have no access to proper tools, materials, or a place to do any real manufacturing, so it was more of a wistful pipe dream unfortunately. I'm not saying I have a fraction of Dale's talent either, but I have taken a few stabs at custom design work and welding in my lifetime too.

So. Having acquired the HBP fuel cell, there were a couple things I wanted to do before installing it and filling it up with gasoline. As it arrived, it had an external threaded filler spigot, with an anti-spill breather valve and tube on the plastic cap. Perfectly functional and eminently practical, but I wanted to be able to have a flat surface to place luggage or a RotoPax fuel cell on top of.







I wanted a low profile flush fitting sportbike type filler cap, but the way the OEM ones are made, they have a rather complex in-tank configuration, with water drain tubes, vent tubes etc., built into the tank itself; beyond my time, skill, energy, and funding to duplicate. The next closest thing is an aircraft or "generic" fuel cap and mount that you find on the usual suspect plastic drag race kind of Jaz, RCI, and so on fuel cells-



This would entail *gulp* cutting off the external spigot and hacking a giant hole the fuel cell. A point of no return...



Now unfortunately, the heat of the original welding of the spigot on to the thin aluminum sheet, had warped the top surface of the fuel cell a wee bit. Not enough to notice when the original cap was on, and it made no difference to the looks/volume/efficiency, but because I was mucking with it and needed a perfectly flat flange surface, it was something I had to deal with. Also, because of the original hole opening near the edge of the top, I had an extremely tiny margin for error to get the flange to fit on and have the new hole juuuuuust eclipse the edge of the hole, yet not be too close the edge of the top/side, making no room for the fasteners to bolt down through. (More on this later)



I filled up and leveled off the dips with two part epoxy (additional areas around the new hole were also filled up and sanded down, bit no pics taken)





Ahh, there we go. (This took a few days worth of filling, sanding, measuring, re filling, re sanding, etc. *pant, pant*)




Now as mentioned earlier, I chose the generic aircraft style filler and mounting flange, but didn't want a red one with chrome ring. Yuck. Also, The method in which they are affixed to a fuel cell is very robust and simple, but offended my eye as to the aesthetics of things. I didn't want a bunch of sticky uppy threaded studs with nylock nuts bolted to them. (sigh, going this route was more complicated and spendy than one would actually imagine...)

I ordered some cool Stainless steel M8 Torx security button head bolts from a place in Australia. They would at least allow for a smoother surface for any luggage to be laid on top of, and they look freaking cool, lol.

Of course this complicated things, though. With the RCI fuel cap, came two steel flanges, with threaded studs tack welded to them. These flanges go inside the fuel cell from underneath, compressing a rubber gasket in between the inside of the cell and the outer flange, to keep everything liquid tight.





Since I wanted to use bolts down from the outside in, this meant I had to remove the threaded studs from the steel rings. Sounds easy, right? Wrong. As it turned out, removing the spot welds holding the bolts on didn't help. I thought I'd be able to simply unthread each bolt out of it's respective hole in the steel ring. Well despite looking like bolts, they were actually pressed in studs, requiring a bloody battle to try and punch out, even after completely cutting off the entire head of the "bolt". Good grief, that was a hellish job. The steel rings were very soft, and the heat from grinding warped and bent them into pretzels, pounding the studs out with hammer and punch made bowl shaped concave divots, auugh. Much work was needed to get them back to some semblance of "flat"...

Oh, and I had no room between the outer edge inner wall of the fuel cell and where the tops of two of the nuts for the bolts needed to be, going through the steel ring. The outer circumference had to be cut off and filed nearly flat, in order to fit up inside and compress the rubber gasket. Difficult to explain, but a chore, trust me ha ha!



Decided to go with the same black rubberized rocker guard paint I put on my HondaBikePro skidplate











The sourcing of fuel lines and 1/8th to 3/16th adapters was another story, but unworthy of going into detail. I glorped Form A Gasket #2 all over every applicable mating surface and fastener thread (ye gods that stuff is messy/sticky, my fingernails will be black for months...) and am letting it set up for at least 24 hours prior to putting the first tank of gas into it. I will report back with how that goes and if I have any hideous disasters with leaks, fireballs, etc., as soon as I can.

I'm sure there is lots I'm forgetting, and will update and/or add in stuff if I remember.


OEM tank breather location and hose



Adapter reducer elbow with appropriate size barbs



General hose routing



As tank lowers to closed



Final look of fuel cap and mounting flange



Time to fill it up...

Distance ridden on tank



Distance ridden on Reserve



Fuel Cell filled up to high as I was comfortable with this first test run (hard to see, but the bottom of the filler cap touches the level of the gas)



Amount of fuel put in the bike's tank, and the amount of fuel put in the Fuel Cell



The good news, is there doesn't appear to be any leaks, the vent holes I drilled seem to work-no pressure hissing or imploding of the cell, or vacuum fuel starvation due to lack of enough vent volume, and I didn't explode in a fireball mushroom cloud, heh heh.

The bad news, is I removed some precious tank volume due to the space taken up by the fuel cap design. I can't put in as much as the way the old external spigot and cap system was. Oh well. All things considered, I'm not going to cry over maybe 500 or so millilitres. I'm grudgingly satisfied so far with the end result. Time and use will tell the true tale, though. Wish me luck!

 

[OldJeff]

Impressive work! And it looks good on the bike. How much gas will it hold?

 

[anglachel]

Looks like a great place to install a backrest!

How much does it hold? And can you show a photo of how it hooks into the main tank (I'm guessing through the vent line, but I'd really like to be able to visualize it)

I did lots of thinking about aux fuel cells while camping this weekend, and I think that a design like this is probably one of the better options, keeps the weight forward (if not low) and (with backrest added) would really make the bike a bit more comfortable to ride for hours on end (also a aftermarket windscreen, hand guards, highway pegs, and a good seat wouldn't hurt either, so I've got along way to go before I get into buying gas tanks). And of course it's when I'm riding for hours on end that I'd want the aux tank in the first place...

 

[turbodieseli4i6]

That's awesome!!! Good job my friend. .

 

[JDE]

Very nice looking!! Great job!! Couple questions. Does the new cap have a vent built in? If not, is there any kind of vent on that tank?

 

[itlives]

Well, this post answers my question in the pics thread - thanks!

Good pictures. I think it looks great on your bike!

 

[JoeTx]

Nice, sure could of used that on my trip. L.B.S where did you tie in to the tank and did you have to lengthen the vent line?

 

[L.B.S.]

Thanks for all the kind replies, gents!

I will add in a picture of the fuel lines and how they attach from fuel cell to fuel tank. I'm kind of embarrassed at how clunky my temporary solution is; I had a real bother of a time trying to find a simple (or so I thought...) adapter/reducer fuel barb going from 3/16 to 1/8. It is nothing I can get in Canuck land apparently, so I will have to try and source one over the internet from a civilized country somewhere, one day.

The OEM Honda breather sticking out of the neck area of the tank turns out to be a wee tiny little thing of the aforementioned 1/8" size, which meant try as I might, I couldn't force the rubber breather line over Dale's chosen outlet. (I think the fuel fitting attached to the fuel cell is actually 1/4" but I picked 3/16" fuel line for an extra snug fit over the barb)

The only way around this was to fashion a bulky brass union pipe thread elbow joint, with a thread-in 1/8 barb on one end, and a thread-in 3/16 barb in the other. I couldn't even locate a simple straight adapter! Oh well.

So the OEM breather hose was removed from the Honda fuel tank neck barb, a small section cut off (approx. 4" or so) and one end attached to the new 1/8 brass fuel barb contraption. The other end simply re stuck back onto the Honda tank vent tube again. The existing, now shorter by 4" vent line doesn't go anywhere, it's just sitting there tucked out of the way.

The new 3/16 inch fuel hose I bought (about 10" or so long) attaches to the other end of the brass elbow adapter gizmo, end then to the fuel cell's outlet barb.

The venting of the fuel cell. What a pain in the butt that was! I spent an inordinate amount of time haunting the web making sure I bought a Vented Style fuel cap. The pictures showed a weird looking little plastic Top hat looking affair screwed onto the top of the cap; it was called and sold as a vented cap, so it was a vent, right? WRONG!! :GRRRRRRR:

After undoing the little phillips screw holding this bit on to see how it worked, (I was already puzzled, having discovered that the molded in holes on the inside of the cap were blind-they didn't really go all the way through :suspicious frown: ) of course my fears were realized. There was no venting going on with the Top Hat thingy! It was a solid disc of plastic, raised up about 1/8 inch off the top of the cap, with no other holes other than the one the phillips screw threaded into! Ridiculous! A completely useless entity.

The closest I came to finding out what this thing did, was a reply from a stranger on the net that it was a vent, but a pressure blow off vent, if the internal pressure inside the tank ever somehow got too high. Not an air intake breather vent. This made perfect sense, but I was still not convinced. The raised plastic disc was molded into the top of the cap as one piece, I looked at it extremely close, and it absolutely did not look like a pressed in fitting. Unless it had a hidden score line around the inside, like car airbags in the dashboard, I just could not see how it could work.

Back to the drawing board. I ended up drilling through the inside bottom of the cap in a couple of places, and then after undoing the Top Hat, drilled a tiny little 1/16 hole in the top of the raised disc in between the edge and the threaded phillips screw hole. I oriented the flange and cap on the fuel cell as to be at the highest point when the bike was on the side stand. The hole I drilled in the disc is on the left "downslope" side. Hopefully water won't be able to go up and over the raised edge when the bike is level, and I'm riding in a downpour...

As to the fuel cell true volume, I don't know yet. I briefly experimented with filling it up with water when I first got it, but that was more to get a feel for how heavy it would be, not so much to measure it's volume. I think it was around 6 and bit litres? I will know exactly and tell all today hopefully.

There is a clever "sump" fabricated in, but due to the nooks and crannies of the form fitting svelte shape, there will be a small amount of unusable gas sloshing about, I imagine. I knew this going in so I am unconcerned; I think it's a piece of artwork Dale made, so am more than willing to live with a few ounces of unusable fuel as a compromise.

 

[OldJeff]

So 1.6 gallons + 3.1 = 4.7 total gallons. At 60 mpg that's a 288 mile range or a additional 100 mpg over the stock tank. Not too shabby, esp. considering it looks a heck of a lot better than two tool tubes with 33 oz. MSR bottles in them. I'm afraid to ask what you've spent on this project

 

[L.B.S.]

So 1.6 gallons + 3.1 = 4.7 total gallons. At 60 mpg that's a 288 mile range or a additional 100 mpg over the stock tank. Not too shabby, esp. considering it looks a heck of a lot better than two tool tubes with 33 oz. MSR bottles in them. I'm afraid to ask what you've spent on this project

You don't want to know how much this little endeavor cost me... Imagine how much you would think of as waaaay too expensive to even remotely justify, then triple or quadruple that number at least. Augh lol. I won't divulge the number 'cause I'm trying to block it out, and plus it's too shameful.

My figuring of the fuel volume is- nominal NC700XA: 14.02 litres (3.70 US gal) + Fuel Cell: 5.507* litres (1.45 US Gal) = 19.527 litres (5.15 US Gal) Give or take.


* I will add extra info to my first post regarding this number

 

[ziggie]

It looks good sitting on the termanator lbs.very good job.

 

[ld_rider]

It appears as though under some circumstances the NC's tank will <not> be vented..Is that correct? I'm thinking since you tapped into the original tank's vent line, when there is fuel in the hose running to the Aux tank (i.e. the vent is blocked) you effectively cut off venting of the main tank.

Even after fuel transfer from Aux to Main you might be running around with an unvented fuel tank....not good:

Think of a "P" trap under your kitchen sink...sorta the same thing can happen here. Water flows via gravity down the sink but when the flow stops, the "P" trap (which contains water) forms a seal preventing fumes/sewer gasses from escaping. Depending on how the hose under the passenger seat contorted itself when you put the seat down, you could end up with a similar vent restriction.

Is the Aux tank vented? One purpose that the taller, original filler neck provided was a place to tap into for a vent. By venting from the filler tube you would have the ability to completely fill the tank (especially when on the side-stand) without losing any capacity. In addition, if you had used a non-vented fuel cap with that configuration and run a hose from the filler neck vent to the rear of the bike, when the fuel/fumes did expand, they would be vented away from your tank/seat area and to an area behind your rear wheel.

How do you control flow from the Aux tank to the main tank? If there is no flow control, my guess is that your bike doesn't have the same emissions as U.S. bikes do, otherwise your carbon canister will eventually flood with fuel, which will stop you in your tracks until it can be purged. Happens here on Gold Wings when guys with Aux tanks forget to turn off the fuel flow valve when refueling.

Might want to think about some quick-disconnects or some other way to stop the flow from the Aux tank to the main tank. A leaking hose at 2am in BFE would mean about a gallon of fuel under your passenger seat. If you go with quick disconnects, make sure they stop flow also..Not all of them do.

It appears as though you still have to lift your seat each time you fill the main tank? Does that put any stress on the hose/fittings?

I've just ordered a 3 gallon Tour Tank to mount on my bike. It will be the second tank I've installed on a motorcycle and since I really don't fully understand all the potential safety issues I do my installs per Iron Butt Association technical regulations. Their requirements aren't very stringent but they are safe, reliable and most importantly (to me) have been tested over hundreds of thousands of miles without a single fireball ;-)

 

[StratTuner]

just to watch you work.... on anything.... is valuable instruction. Well done!

 

[L.B.S.]

It appears as though under some circumstances the NC's tank will <not> be vented..Is that correct? I'm thinking since you tapped into the original tank's vent line, when there is fuel in the hose running to the Aux tank (i.e. the vent is blocked) you effectively cut off venting of the main tank.

Even after fuel transfer from Aux to Main you might be running around with an unvented fuel tank....not good:

Think of a "P" trap under your kitchen sink...sorta the same thing can happen here. Water flows via gravity down the sink but when the flow stops, the "P" trap (which contains water) forms a seal preventing fumes/sewer gasses from escaping. Depending on how the hose under the passenger seat contorted itself when you put the seat down, you could end up with a similar vent restriction.

Is the Aux tank vented? One purpose that the taller, original filler neck provided was a place to tap into for a vent. By venting from the filler tube you would have the ability to completely fill the tank (especially when on the side-stand) without losing any capacity. In addition, if you had used a non-vented fuel cap with that configuration and run a hose from the filler neck vent to the rear of the bike, when the fuel/fumes did expand, they would be vented away from your tank/seat area and to an area behind your rear wheel.

How do you control flow from the Aux tank to the main tank? If there is no flow control, my guess is that your bike doesn't have the same emissions as U.S. bikes do, otherwise your carbon canister will eventually flood with fuel, which will stop you in your tracks until it can be purged. Happens here on Gold Wings when guys with Aux tanks forget to turn off the fuel flow valve when refueling.

Might want to think about some quick-disconnects or some other way to stop the flow from the Aux tank to the main tank. A leaking hose at 2am in BFE would mean about a gallon of fuel under your passenger seat. If you go with quick disconnects, make sure they stop flow also..Not all of them do.

It appears as though you still have to lift your seat each time you fill the main tank? Does that put any stress on the hose/fittings?

I've just ordered a 3 gallon Tour Tank to mount on my bike. It will be the second tank I've installed on a motorcycle and since I really don't fully understand all the potential safety issues I do my installs per Iron Butt Association technical regulations. Their requirements aren't very stringent but they are safe, reliable and most importantly (to me) have been tested over hundreds of thousands of miles without a single fireball ;-)

Venting is venting; the main tank does not know, all it cares about is that there is air pressure above it, rather than a vacuum. Instead of thinking about it as two separate tanks, picture the system as one slightly larger tank of an oddball shape.



All that is needed in a gravity fed fuel container is a positive pressure opening in the highest point. Which is what the OEM tank is, and in effect, the addition of this fuel cell with vented cap.

The US is the only (motorcycle) model that I know of with the emissions requirement of a vapour recovery charcoal canister system. Canada does not have this, nor a fuel overflow line to a catch tank- just out and down to the ground. Directly beneath the bike/rider. With the vented fuel cap I am using, it is as far away from the bike/rider as it can be, really.

It was exactly the same with my BMW (which I note had many owners complaining bitterly about the system not working properly and causing all manner of havoc, prompting most of them to remove all that stuff and throw it away until BMW redesigned the set up)


As I have done this before, and the previous owner/fabricator of the fuel cell system used the very same tank I now have with great success, stringent Ironbutt rules and regulations are something I'm not concerned about following, to be honest.

Yes, if I want to fill or top up my main tank, the fuel cell must be empty. I can, if I choose though, keep topping up the fuel cell as I ride, but that would be tiresome as it only would get me 140-150 km's at a time all by itself.

I am not going to be lifting up the fuel cell to access the main tank when it has fuel in it, so the weight of the fuel in the cell isn't a concern with stressing hinges. The weight of the cell is at least 100 lbs lighter than the average passenger, so I'm not concerned about any other stresses on hinges and or supports etc., either.

The fuel line is robust with very thick walls, it strongly resists kinking to the point of cutting off flow, and that is also the reason it is looped in the manner shown, to avoid stretching or sharp angles. I have no fears of it being affected by the fuel cell going up and down a couple inches.

Even my old GSXR750 had a simple OEM vent hose sticking up directly from the top of the tank, right next to the fuel cap. The hose went up and then down into the steering stem. Which is hollow of course, and the terminus happens to be directly above the headers, lol.

I did (and will still) look into putting an inline fuel quick disconnect or shut off valve. I mentioned this earlier in one of my musings on the subject.

 

[ld_rider]

As I have done this before, and the previous owner/fabricator of the fuel cell system used the very same tank I now have with great success

Sounds like you did your homework and glad it is working great!

 

[L.B.S.]

Sounds like you did your homework and glad it is working great!

Well I hope so, anyway, lol!

Thank you for your friendly concern and observations, I appreciate all input, trust me. I don't really wanna be a fireball on the 6:00 News!

 

[L.B.S.]

I jinxed myself!

A word of caution if someone is going to do a fuel cell, or muck with the Honda OEM fuel tank breather hose for any reason.

My bike has been sitting all last afternoon, the night, all day today while I was at work. Everything good. I'm in my room watching TV, and I think I smell gasoline. Haha, don't be paranoid, self! *sniff* *sniff* No, now I really do smell gasoline! I open my curtain to look at my bike, and see gas pouring out of it. Auuugh! WTF! OMG! Great jumping Jehoshaphat!

I fling on some shoes, run outside, and all I can think of is to push my bike out from under my landlord's deck. I quickly unlock the cable through the back wheel and frame, unlock the bike's steering lock, and give two and a half great leg pumping pushes forward, and...*CRUNCH* *skid* *crash*

[insert utterly bewildered looking LBS here, with bike laying on top of him]

[gasoline just POURING out of bike now, me laying in ever growing pool, completely freaked out, lol]

I had put on a brand new little U-Lock through the front disc brake last night, and forgot all about it.

The warning about the OEM breather hose part? Well apparently they are just fine for use as a breather hose, but having liquid petrol in them makes them go mushy and fall apart! There is an outer light gray thin layer that just flaked and sloughed off like the skin of a marshmallow, when you stick it in the fire for too long, and the inner black layer cracked in half like a brittle piece of licorice.

That was the last thing I would have ever imagined going wrong, in this whole project. Go figure, eh?

Oh, and the brake rotor is ok, nothing appears to have been damaged regarding the caliper, the bike brakes just fine and runs true, but now my ABS light is always on. I think the sensor took a whack and got shifted slightly crooked or distanced itself from the tone ring enough to kibosh the system.

So how was your evening? lol

ps
I managed to put my back out during this, and am walking around like Quasimodo, my two week vacation that I had big plans for, starts this Friday. Oy Vey.

 

[Antarius]

Yes, be sure to use fuel line - not vent line!

Glad you mostly survived though! Ana great looking tank...

 

[670cc]

Wow, that story sure took an unexpected turn! Sorry to hear about your back and your bike. I'm sure you'll get better/figure it out. Live and learn, no pain, no gain, etc.

 

[turbodieseli4i6]

That's a very big bummer! I hope your back gets better very soon. . I'm sure you will get the tank working the way it should in short order.