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

[Wildfire]

Not to turn this into a flame war (sorry), but I don't see this as reckless endangerment of the public. Yes there are some personal risks for the rider and his property which are being mitigated by continued monitoring of the tank condition and the adding of a breather line to ventilate the tank.

I can understand how someone from Atlanta can be flabbergasted that some people just aren't happy with the range on their bikes. Open Google Maps, zoom out until you can only see the major highways, then scroll up to Canada. See the lack of major roads? Outside the main travel corridors it isn't uncommon for their to be hundreds of km between gas stations that *usually* have fuel. Scroll over to Sweden, their road scenario looks somewhat similar. I might be wrong here but I would think that people who want more range generally aren't the people stuck in bumper to bumper traffic surrounded by other people. If our bikes do turn into raging fireballs the only ones likely to be affected are ourselves.


I did see that Camel ADV is developing a external rear tank for the Africa Twin that is compatible with some rack systems. Once it is available I would love to see if I could make it fit inside the rear rack of my NC. That would be the ideal, if pricey solution.

The extreme usefulness of the frunk is the only reason I have not installed the 9.5 liter tank that I have alluded to earlier.

 

[L.B.S.]

Just as it should be, everyone is entitled to their own take on things. For or against, good or bad, but I urge folks to be perfectly civil in how you get your opinion across.

 

[Deleted member 5383]

Glad the NC isn't a gas pig -- however one chooses to carry extra fuel there's less weight involved too, for a given range.

 

[davidc83]

Not to turn this into a flame war (sorry), but I don't see this as reckless endangerment of the public. Yes there are some personal risks for the rider and his property which are being mitigated by continued monitoring of the tank condition and the adding of a breather line to ventilate the tank.

A 400+ lb flaming bike running into bystanders, bicyclists, pedestrians; same flaming bike running into a door of a car, trapping the driver in the car-panics, cant get out and burn along with the burning bike. These are just examples of reckless endangerment to the public. Personally, I wouldn't want to be riding next to him, behind him, or anywhere in the vicinity-gas blowing up inside of the frunk is going to have shrapnel (mostly hard plastic) going every which way. Catching on fire in remote areas-causing wildfires can endanger the public.
To stay on topic, to the OP; if the container is discoloring, more than likely the material is breaking down due to not being made for gasoline or petroleum products. If you are going to keep this configuration, use a container specifically made for gasoline.

 

[Beemerphile]

Being nice, this frunk tank is a horribly bad idea, or at least, it is horribly implemented. Lots of safety issues here, not just for the rider, but for others as @davidc83 pointed out. I would add the potential danger to an unknowing passenger on the machine.

1) The container and its cap seal are not rated for pressure, vacuum, or flammables. It is a water container. Reading the warnings on the gas pumps, it is not even legal (in the US anyway) to fill this system with gasoline.

2) "Proper" vent means it has a roll-over valve. If this bike goes flat side up, the fuel will leak even if the tank does not rupture. The prior state of running with the cap partially open was much worse.

3) The frunk is not rated for this much weight. It sits on plastic mounts. The load rating of the frunk is not just how much static weight it can hold without breaking, but there are implications for crashworthiness as well.

4) Current approved HDPE plastic fuel tanks for vehicles are normally 6-layer. Internal layers of polyamide or ethylene vinyl acetate are used to prevent fuel permeation. Obviously fuel permeation is occurring with this system.

5) The fill area of OEM tanks have overflow containment areas and are piped to drain to a safe area. A fuel spill into the frunk would put it into an uncontrolled area that includes the battery, fuse panel, etc. Ever had a fuel spill when gassing up? Where does the gas go with this arrangement? Where does the frunk drain to?

6) In a crash, there will be a severe impulse load that could easily rupture the non-pressure rated container. Then three gallons of gas is instantly dispensed into the crash scene which could engulf all vehicles involved in the crash. If the crash causes an electrical short or battery failure, a bad result is almost guaranteed. A crash would have the same impulse load on the container as throwing the container against a wall at the same speed. How many miles per hour do you think this thin-walled non-pressure-rated container and closure can stand before it fails and dispenses its contents? I don't know either, but my guess is not many. As an example dropping the full container from a 16 ft. height would simulate a 22 mph collision. What happens to it? Yep.

7) Since the frunk is fairly well closed, vapors could build to the explosive limit and there would be no warning. Then ANY ignition source can mean a conflagration.

I strongly, and in the kindest way possible, recommend abandoning this system. - Lee

 

[AsureDawn]

Just a note: gas fumes wont easily ignite when the air is saturated with gas, even with a spark. With the proper mixture, it will easily ignite.

 

[Beemerphile]

Just a note: gas fumes wont easily ignite when the air is saturated with gas, even with a spark. With the proper mixture, it will easily ignite.

This is true. The fuel / air ratio has to be between the stoichiometric limits for combustion, however, as an engineer who has built Class 1 Division 1 explosion-proof manufacturing facilities, I can say that the way explosions are prevented is to keep the fuel level well below explosive limits and eliminate ignition sources. I have never heard of keeping the fuel level ABOVE explosive limits as a means of mitigation. The problem here is that the fuel level is unknown and uncontrolled. The possibility exists for it to reach or pass through explosive limits. Secondly, there is no knowledge of or attempt to control ignition sources within the space. Thirdly, static ignition sources are possible within the space even if the electrics were intrinsically safe (which they are not).

 

[AsureDawn]

This is true. The fuel / air ratio has to be between the stoichiometric limits for combustion, however, as an engineer who has built Class 1 Division 1 explosion-proof manufacturing facilities, I can say that the way explosions are prevented is to keep the fuel level well below explosive limits and eliminate ignition sources. I have never heard of keeping the fuel level ABOVE explosive limits as a means of mitigation. The problem here is that the fuel level is unknown and uncontrolled. The possibility exists for it to reach or pass through explosive limits. Secondly, there is no knowledge of or attempt to control ignition sources within the space. Thirdly, static ignition sources are possible within the space even if the electrics were intrinsically safe (which they are not).

Well, the little red gas cans you can buy in the US have no vent, not even one to allow proper pouring, which is why they get all bloated if you leave them in a hot environment (which is not a good idea, btw).

I do agree it's not a good solution in this case--the container just isn't designed to carry gasoline in the first place, places strain on the frunk which the designers hadn't built it for, and then there is the possibility of sparks being present. Though, I honestly think its more likely to break the frunk and then melt the can, gas igniting on the hot engine or some other external ignition source, than some random spark inside the frunk causing ignition, I'd rather be safe and get something purpose built than take any chances with this.

 

[TGorman]

I can understand how someone from Atlanta can be flabbergasted that some people just aren't happy with the range on their bikes...

You missed my point. I'm not arguing the desire to hold more fuel, I'm arguing this application. There is a safe way to do it and there is this way.

 

[Deleted member 5383]

repetition: the sincerest form of repetition.

 

[Wildfire]

You missed my point. I'm not arguing the desire to hold more fuel, I'm arguing this application. There is a safe way to do it and there is this way.

You are right, I must have been tired and grumpy and taken your post without context, though to be fair it was hard to tell exactly what your specific concerns were. Re-reading my post the middle bit was straying towards a personal attack rather than sticking to the merits of the system, I apologize.

A big thank you to Lee (Beemerphile) for his well thought out post explicitly pointing out the dangers and flaws in the system currently being discussed. When we know what the problems are we can work towards solutions.

I am still not against the idea of having a secondary fuel tank in or replacing the frunk, but agree that steps should be taken to minimize risk whenever practicable.

 

[Wildfire]

Sooo, I was thinking about this and bored so did some digging.

The CTX has a pretty anemic tank at only 12 liters that hides under the body work. The body work also hides an apparently identical frame section to our NCs. It might be possible to replace the plastic frunk bucket with a metal CTX tank.

I'm not sure if the mounting points line up or not but if they do this might be a relativity simple way to get a dual tank NC that looks stock without using unapproved containers. Add in a splash guard, and figure out what to do with the battery and most of the issues are taken care of.

Used CTX700 tanks are going for $20-30 on ebay. Of course it's rarely that simple but this might be a possibility.

 

[AsureDawn]

Sooo, I was thinking about this and bored so did some digging.

The CTX has a pretty anemic tank at only 12 liters that hides under the body work. The body work also hides an apparently identical frame section to our NCs. It might be possible to replace the plastic frunk bucket with a metal CTX tank.

I'm not sure if the mounting points line up or not but if they do this might be a relativity simple way to get a dual tank NC that looks stock without using unapproved containers. Add in a splash guard, and figure out what to do with the battery and most of the issues are taken care of.

Used CTX700 tanks are going for $20-30 on ebay. Of course it's rarely that simple but this might be a possibility.

For one thing, you'd need to figure out another way to access the fuses and battery. But it's a start.

 

[Mi_ka]

so a meet up with an CTX guy is in order to see what can be mixed and matched

 

[Beemerphile]

so a meet up with an CTX guy is in order to see what can be mixed and matched

Now you are cooking with gas! When you give up on the objective of "how quick can I be finished" and replace it with "how well can I do this thing" then you have a chance of a good outcome. I considered a frunk tank for quite a while, but it had to remain removable for battery and fuse access unless I wanted to re-locate those. Even with a proper fuel enclosure, I would never have felt comfortable putting that much weight in the frunk without boring through the bottom of the frunk and finding hard frame locations to mount metal supports on. Though removable, the tank would need to be mounted to the hardpoints to keep it from becoming a projectile in a collision. As a test, put a bowling ball in your seat and hire a crash dummy to crash your car into a wall at 30-45 mph. See how far into the dashboard the bowling ball is buried. The current angle you guys are considering (CTX adaptation) is a neat way to go about the challenge. I like it.


Personally, I gave up and mounted a Rotopax on the bike. A rare case of me being sensible...



Rotopax has it all over the generic red Jiffy cans. It is thick (like a camel tank) and has a solid closure. The mounting system and hardware are 1st class and are lockable. They are shaped in a good way for carrying them. They are rated for mobile use (not just filling lawn mowers). Looking at the white interior, I'd say they were probably layered to prevent permeation. Two one gallon Rotopax units and the NC can travel the largest gap between gas stations in North America. It is all anyone REALLY needs.

So, when I prepped my GS after the Beemerbike went to live with Greg, I took a similar approach...



But alas, all one REALLY needs often isn't all one really WANTS. I got used to the 10 gallon fuel load on my R1150 and it is hard to go backwards. I had kept the tank when I sold the R1150, so I decided to put it back in service. It is a 5-gallon Summit Racing TIG welded aluminum tank and is approved by the Iron Buttt Association and the NHRA. Although it is one of the tanks specifically accepted by the IBA, they will still look at the plumbing and how it is mounted during a tech inspection. My first inclination (the easiest thing to do) was to mount it on the flat Jesse luggage rack that replaced my rear seat (similar to the HondaBikePro rack on the NC. The only problem, looking closer, is that the whole thing is mounted on a plastic carrier and held on the bike by a thin spring steel latch. I would never put a wood stove on a combustible floor and I will never put a gas tank on a plastic perch. Just ain't. Nope.



So I took it all off and went looking for hardpoints on the frame I could mount to. Under the skin I found five vertical and four horizontal mounting points that I could use.



So I cobbled up a couple of side channels from 3" aluminum angle that would hit all of the mounting points.



Spacers had to be made to bring the hardpoints up to the right positions...



Then I fabbed a top plate from 3/16" aluminum plate and painted them all hammertone silver to match the Jesse bags.



Since the seat lock was on the discarded rack, I fabbed a replacement using a cabinet lock..



This shows how the rear mounting points are configured with spacers to hit the hardpoints.



The tank has redundant vents with rollover valves. The plumbing is AN8 transitioned to 5/16" fuel injection hose.



Here is the finished product.



You don't know how close this tank came to being mounted on the NC in place of the Rotopax. I had determined that the frunk was a handy enough place and I didn't want to tackle the obstacles only to lose the use of it. If I were still in possession of the NC and wanted more attached fuel, I would mount an approved tank on the HondaBikePro rack after proving to myself that the mounting was secure enough (changing it if it was not). In other words similar to what was done here with the GS. I only publish the GS pics to give you an idea of what you might have to identify and overcome with the NC.

I generally believe in seeing how well I can do anything rather than how quickly I can finish. But with safety related projects, I think it even makes sense for "normal" people to proceed that way. In my mind, this is one of those.

 

[TGorman]

You are right, I must have been tired and grumpy and taken your post without context, though to be fair it was hard to tell exactly what your specific concerns were. Re-reading my post the middle bit was straying towards a personal attack rather than sticking to the merits of the system, I apologize.

No worries, I had stated specifics in a previous post and was trying to avoid

repetition: the sincerest form of repetition.