Placing a +- 3 gallon aux tank in helmet compartment on a NC750X how to if possible.

[Pettersson]

Well, if I always wanted to be on the safe side, I wouldn't ride a motorcycle at all. No airbag, no safety belt and not much of a deformation zone.

Yes I plan to add a proper breather tube, as I suspect when the weather gets warmer the fumes might expand more than what's healthy for the tank.
There's been no wear on the tank whatsoever, seems like liquid pushes it in all directions making it like glued to the frunk. So far so good.

 

[woppyvac]

So how many miles do you get between refills?!

 

[supertux1]

I believe the weight limit on the funk is something like 10 or 11 pounds. Does the the thing slosh around and bash the funk bucket when you practice emergency stops with it half full?

As for the container, as long as there isn't any chemical degradation/melting of the plastic and all you're worried about is mechanical stress, you could probably wrap it creatively in duct-tape.

Personall, I'm going to get a couple of rotopax to go over my never to be used passenger seat and shove my rain/heat/cool/helmet gear in the frunk.

 

[Pettersson]

This time, 696km before red light came on.
The tank seems to be very still in there, but I haven't tried any serious off-road driving so far.

 

[Pettersson]

*bump*
Time for an update.
With the arrival of warmer weather here, I had to add a proper tank vent (as someone here suggested) to avoid fumes to accumulate att the bottom of the frunk. This also means I can have the cap closed at all times. Fill-n-forget kind of. Safer too.
Also, I've been doing some off-road driving now and still no wear on the tank whatsoever. Seems it doesn't move at all. That was my biggest concern so I'm happy.
And so you know; the frunk-tank is emptied first and it can be disconnected at any time. On top of that, there is some evaporate-condense magic going on. I think because the frunk is a little warmer than the regular tank, fuel evaporates in the frunk tank, goes over to the regular tank and condenses there. I guess it happens when the bike is parked with the engine still warm. This means the last drip in the frunk tank goes away, even the fumes seem to go away.
On my 7:th fillup now, I think, and there has been gas in the tank since december.

 

[paprides]

Clever set up, and relatively inexpensive.

I too had considered a "frunk fill," set up but was put off by the lack of weight carrying ability (although I know with a talented fabricator and enough money any problem can be overcome).

In my dreams I have an aluminum 3 gallon form fitted tank in the frunk that is hosed directly to the main tank via a bung drilled into the main. Both tanks would be vented to the exterior. That would leave some room in the frunk for necessities, balance the weight properly….and just be cool.

But for now, my fuel carrying capacity is a choice of one of two aluminum tanks - mounted on the rack - that drain into the main via gravity (through a modified fuel cap)

 

[tonylathes]

A sound idea

Hi all.

This is my solution to the problem, I've always had problem with range, as there's far between gas stations here at the countryside.
When I don't need fuel, there's a gas station. When I really need fuel, then there is none.

I have a similar fitting on my BMW F800GT that works perfectly. The breather pipe from the main underseat tank is taken to a 12 litre steel tank strapped across the pillion part of the seat. The pipe into the aux tank goes in vertically and is connected to a tube with a weight on the end to hold it down (you can buy these from cart racing stores). Suction from the main tank draws fuel from the Aux tank through a pipe fitted with a quick disconnector. A one-way breather fitted to the aux tank. Thus equipped the range can, with care, be extended to 400 + miles. As I'm thinking of buying an NC750, it's good to know that a similar system will work.

 

[TGorman]

I'm in awe of this modification. So much potential for disaster. Here in the US, we are not even legally able to transport fuel in anything other than a container specifically made to hold fuel, let alone do something like this as an auxiliary tank. When that thing cracks/breaks/punctures I sure hope its when the bike is off and parked in the garage and not when you're zooming down the road. Spewing gasoline on a hot/running engine is not something I would want to experience. Also, I sure hope you do not get involved into a collision. Fuel tanks on motorcycles and cars have impact safety regulations for a reason. I'm not one to bash others modifications/style/choices they make, but this is reckless and extremely dangerous not only for you, but anyone that may hit you or you run into. Just get proper safe fuel cans and attach them in the proper method. Respectfully.

 

[TN Thunder]

A couple of things come to my simple mind. As mentioned in one of the threads above, weight in the frunk may cause some problems. Another issue concerning weight is that now your center of gravity is way off from bike design, you're going to be about 20+ pounds heavier on top which can make the bike handle different. I would use fuel paks which are safe and you can give your butt a break while pouring fuel into the tank. They come in 1, 2 and 3 gal. sizes. In a set up like you've shown you can always buy a 12v gas pump and just suck it out of one container into your fuel tank. They are not very big and don't cost very much. I do know what you mean about gas stations located when you need them. Out on some of the roads I have ridden I have clinched the seat several times until that gas sign shows up on the horizon. One reason I always liked a tank with a reserve.

 

[anglachel]

*bump*
Time for an update.
With the arrival of warmer weather here, I had to add a proper tank vent (as someone here suggested) to avoid fumes to accumulate att the bottom of the frunk. This also means I can have the cap closed at all times. Fill-n-forget kind of. Safer too.
Also, I've been doing some off-road driving now and still no wear on the tank whatsoever. Seems it doesn't move at all. That was my biggest concern so I'm happy.
And so you know; the frunk-tank is emptied first and it can be disconnected at any time. On top of that, there is some evaporate-condense magic going on. I think because the frunk is a little warmer than the regular tank, fuel evaporates in the frunk tank, goes over to the regular tank and condenses there. I guess it happens when the bike is parked with the engine still warm. This means the last drip in the frunk tank goes away, even the fumes seem to go away.
On my 7:th fillup now, I think, and there has been gas in the tank since december.

I recall that there is a drain hole at the bottom of the frunk (under the section for holding the manual) so I don't know that fumes building up would be a problem, then again you might very well be blocking that, which might be a concern because it can't perform it's primary function of keeping condensation from forming in the frunk, of course there isn't much space for condensation with that tank in there, so maybe that all cancels out.

Certainly something to be aware of since that drain hole drops down onto the engine, so a leak would go to the hot engine, might even be worth considering plugging it up somehow (or maybe that will make everything worse, I really have no idea.)

Curious with the collapsible bag, does it collapse into the frunk as it empty's out?

 

[Mi_ka]

I certainly hope I do talk b*llshit here and it always works 100% perfectly for ever:

The whole setup looks very nice and tidy and no fumes concentration is reported so far
BUT
there can be just one unfortunate series of circumstances to make the whole idea go up in fumes, literally
as proper gas fumes concentration and the not so rare spark (e.g. static electricity) could just mean ka-boom waiting round the corner

If I was into putting a proper tank there, I would take the frunk cover completely off (so no inflammable fumes closet possible) and manufacture a properly shaped aluminum frunk slip-in tank with a top finish matching the rest of the bike.

On the other hand, 12 litres of ... warm soup there could work wonders for the spirits of all the riding company during a winter ride {:O]

 

[telecam]

Hi all.

This is my solution to the problem, I've always had problem with range, as there's far between gas stations here at the countryside.
When I don't need fuel, there's a gas station. When I really need fuel, then there is none.

The tank itself is a 15 liter collapsable fresh water container for campers, very cheap.
Tubing and valves are 4mm pneumatic and fittings are of push-in type. The bulkhead fitting is a "Revotec Self Sealing Hose Take Off Kit, 1/8" NPT" from Ebay, and quite not-cheap. I threaded it on the inside as well to add one more fitting with pick up tube. The 90 degree 1/8" fitting and Y-gate was found in my workshop mess. Valves are only used if I decide to remove the frunk tank for some reason.

Yes, everything seems to cope with petrol. Yes, the tank is 100% safe (until it begins to leak). No, it hasn't done that yet ( 1 month testing).

It works better than expected. The fuel pump creates underpressure in the original tank, which draws fuel trough the tube from the frunk tank. This means the frunk tank is emptied first. I can fit about 12 liters in it.

After refill I keep the cap closed on the frunk tank, and opens it after about 50km to avoid fuel spill. I might add a proper breather tube some day, but by doing like this I dont need to.


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Peter.

Not wanting to be judgemental but as clean as your installation looks, I think this really defies common sense and basic safety rules. You are using a non-rated container to hold a flammable liquid surrounded by a battery and various electronic components and all this on top of a hot engine. In case of a container failure or even a mild crash, you are not only putting yourself at risk but also your passengers and any surrounding persons.

 

[Pettersson]

Time to bump this thread with an after-season report for you interested.
9000 km's with this installation and I don't want to be without it. A 750 km range was a joy to get used to.
My tank has got a very slight brown color by now. Don't know if it's the plastic itself or some deposit inside. Or age.
It's still as flexible as before and no sign of wear.
Also, the tank smells of fuel. Not much but noticeable. I believe some molecules of gas actually permeates right through the plastic,
that's the only explanation I have.

Anyhow, the will be at least one more season!

 

[Mi_ka]

be careful and check it often - as we say over here, "may I eat my tongue" but it only takes one unfortunate domino of factors

 

[Wildfire]

If it is discoulored I would be tempted to swap out the tank and do some destructive tests to the original to make sure it is nothing to worry about. A new tank for $20 (or whatever it cost) would be cheap peace of mind.

I have started to really appreciate the frunk space so am now leaning towards mounting some sort of aux tank to the inside of my rack, though a extra tank in the frunk would be much easier and less expensive to pull off. I already have the 9 liter antifreeze container that fits nicely...

 

[ST13Fred]

Carrying gasoline on a motorcycle outside the OEM fuel tank is very dangerous and something I would NEVER consider as a semi-permanent installation.
I routinely strap 4 approved plastic cans totalling 7 gallons in a soft pizza bag to my NC for 3 miles and that's it. I'm a little nervous doing that.
Any petroleum base product hardens with age and will fail eventually........it is not if......but when. My old age is showing here so only will say.....be careful!

 

[Deleted member 5383]

Totally happy with Rotopax. For the types of rides I go on, doing a fill-up when out of range is not in the least a deterrent. Nor is refilling it the next time I go out. It's great that I can share it between MCs.

 

[Ruggybuggy]

How would any kind of aux tank handle a crash? Honda has designed it's tank to withstand and accident and prevent fuel spilling out if the the bike was in an accident. Putting an aux tank in the storage compartment made from material not designed to hold fuel and then running "home made" fuel lines compromises the safety built into the bike. Imagine getting into an accident and the aux tank splits open. The fuel catches on fire from the sparks generated from the sliding bike and you end up soak in gas. Also another consideration is how do you think the police and your insurance company would feel about gasoline carried in a container not approve for fuel? In Canada it actually illegal to carry fuel in container not approved for fuel.

 

[davidc83]

Ok guys, give the OP a break. If he wants to be a rolling ball of flames and smoke down the highway-it is his choice. His idea has merits even though the implementation is lacking.

 

[TGorman]

I'd give him a break if his actions would not or could not have implications on other people. But he is risking the lives of others. Sorry, no breaks for him. This is 100% reckless.