Frunk Auxiliary Fuel Tank?

[PHX-AZ-700X]

I have been looking at buying an NC700X as my next bike. I want a larger bike for touring, and I have a CBR250R right now, and it is a little small/under powered for heavier loads.

I see that many people use the frunk for short trips, which is awesome and exactly why I want the bike.

For much longer trips, 700 miles plus, I would use side and top cases.

BUT, has anyone thought about turning the frunk into an auxiliary fuel tank? I am talking about making a form fitted fuel tank that just fits inside the frunk with its own fuel pump to feed the main tank under the seat. I bet you could fit an extra 18-20 Liters (about 5 US gallons) in that space...

Has anyone seen anything like this?

 

[netizen]

Haven't seen that done yet. But several have removed the rear seat and put both gravity fed and pump fed aux tanks there. I think someone even put a backrest pad on one that was gravity fed.

I know Beemerphile has a pump fed aux tank on his bike.

 

[PHX-AZ-700X]

I did see the thread of the aux tank that replaced the back seat, and I do like that idea, especially because it adds a back rest. I could envision a large ATV style flat fuel cell to go under a top case to add a few gallons, but at the same time I don't want to make the bike too top heavy. Gravity feed would be the easiest choice.

I will keep thinking on the idea, and as soon as I get my NC700X next month, I will start tinkering.

 

[Fuzzy]

It can be done, but the frunk is probably the most loved feature of the NC and you will give that up.

Where do you plan to ride that is 600+ miles between gas stations?

 

[dduelin]

The NC motor is fuel injected and requires fuel at 50 or 60 psi in the injector. The bottom of the underseat gas tank is probably above the bottom of the storage compartment - I haven't looked but I think so. If so gravity feed would not get fuel to the pickup point of the existing fuel pump.

 

[turbodieseli4i6]

It's been brought up before, but no one has done anything yet. If you are the first to make one, I know of one sale you would get. I would like a little room left, say the top 3'' for gloves and stuff. That would be great.
Give me 6.5-7 gallons total and I would be a happy camper.

 

[Spaceteach]

While it should be possible to fabricate an aux tank for the frunk, and there have been posts about just putting a fuel container in there, I don't think I'd want to. This is just personal opinion, but I'm not sure how safe it would be. Unless you have a really good way of venting any vapors to the outside of the compartment, couldn't fuel vapors build up in the frunk? Since the battery and fuse box is located just in front of the compartment it seems to me that a spark from a loose battery or wiring connection combined with a source of fuel vapor could make for a really bad day.
I may be totally off base (and probably am), but I do know that on boats placing a fuel tank in an enclosed space requires a pretty good ventilation system.

Bob

 

[Gdawg]

Hello,
I saw the picture of the guy with a plastic tank in the frunk. Very bad idea. Your suggestion is spot on.

G.

 

[turbodieseli4i6]

Myself, I don't want the gas ventilated with O2. I want 100% liquid gas and vapor.

 

[Spaceteach]

Myself, I don't want the gas ventilated with O2. I want 100% liquid gas and vapor.

That would be great, but I don't think anyone has been able to come up with a way to do it. In order for the fuel to go from the tank to the engine, something has to replace the volume in the tank previously occupied by the fuel. I'm pretty sure that's why the fuel tanks in cars, bikes, boats, etc. either have a separate vent or a vented cap. In other words an empty fuel tank doesn't contain any fuel, but it is full of air. The tank doesn't care what replaces the fuel, but something has to, and about the only thing out there is good old fashioned ambient air.
At any rate I'm not saying a frunk fuel tank can't be done, just that you'd have to come up with a way to make sure any vented fuel vapor can't accumulate in the frunk. Personally, by the time the stock tank gets down to the infamous red flashing light on the instrument cluster I'm more than ready to get off the bike anyway, and I figure I might as well re-fuel while I'm at it. If I did feel the need to carry extra fuel, I'd prefer to carry approved containers in some location other than a watertight frunk. Of course, that's just my personal opinion.

Bob

 

[Old Can Ride]

See HondaBikePro thread "new fuel tank for nc". This fuel tank goes on the passenger rear seat. He is a Honda Dealer and a good fabrication person. This is the person to contact for such a tank. A custom fabricated tank will not come cheap! I fabricated a carrying unit to carry two 1 1/2 gallon tanks (3 extra gallons) on my bike. Can not ever tell the tanks are there, as weight is only about 20 lbs. A number of companies sell these quick detach tanks, and they are what a lot of biker's who travel long distances use. This gives me about 340 miles between gas stations. I run out of gas on a regular bases, so I know this works.

 

[Larryb]

See HondaBikePro thread "new fuel tank for nc". This fuel tank goes on the passenger rear seat. He is a Honda Dealer and a good fabrication person. This is the person to contact for such a tank. A custom fabricated tank will not come cheap! I fabricated a carrying unit to carry two 1 1/2 gallon tanks (3 extra gallons) on my bike. Can not ever tell the tanks are there, as weight is only about 20 lbs. A number of companies sell these quick detach tanks, and they are what a lot of biker's who travel long distances use. This gives me about 340 miles between gas stations. I run out of gas on a regular bases, so I know this works.

View attachment 7604

Now that is one nicely equipped NCX. If you dont mind me asking where did you get the highway pegs from??

 

[Old Can Ride]

Nana Chou accessories:

Rox Riser “2”

J&M Drink Holder

Acerbis Hand Guards

Mirror Extenders

Bike Master Power Outlet

Arkon Iphone Waterproof Holder

Universal Vista Cruise Control

Cramp Buster

Utopia Back Rest

AMS Comfort Max Sheepskin Gel Pad Large

Rivco 7/8” Highway Peg mounts for GL1800

Rivco Anti Vibration Pegs Black Powder Coat

Givi Engine Guards

Givi Trekker Fog Lights

Givi Trekker 33 liter Saddlebags

Givi Trekker 54 liter Trunk

Givi Trekker truck and saddlebag mount

Koplin 1 ½ gal Fuel Pack Jr with Mount

¾ Square tube Homemade Gas tank mounts

2 Tooltubes mounted Inside Givi Racks

Honda Center Stand

H&B Skid plate

Interphone Head Set

Iphone

 

[L.B.S.]

GDawg- do tell about the very bad idea. Go into great detail please, I'm curious.

 

[Dave D]

Don't forget that the Frunk has a weight limit of 5kg as well and the engine is getting hot right below the Frunk.

To quote the manual

Never exceed the maximum weight limit.
Maximum Weight: 5.0 kg (11.0 lb)
Do not store any items that are
flammable or susceptible to heat
damage.

 

[n30r3l0ad3d]

Don't forget that the Frunk has a weight limit of 5kg as well and the engine is getting hot right below the Frunk.

To quote the manual

Never exceed the maximum weight limit.
Maximum Weight: 5.0 kg (11.0 lb)
Do not store any items that are
flammable or susceptible to heat
damage.

Good thing they didn't say anything about alcoholic beverages, cause I frequently transport some in my frunk

 

[L.B.S.]

There are many things in life I adhere pretty strictly to as far as warnings, rules and regulations go, many I cautiously exceed with righteous paranoia and observational note taking, and many more I contemptuously flip the bird at.

I would imagine pretty much everybody here has their own little set of justifications for ignoring many of the stipulations as set out verbatim in the manufacturer's list of dos and don'ts, with dire warnings of disastrous calamity if they aren't heeded.

Meh. YMMV. Everyone has to make their own call with what they feel comfortable with.

 

[Larryb]

Nana Chou accessories:

Rox Riser “2”

J&M Drink Holder

Acerbis Hand Guards

Mirror Extenders

Bike Master Power Outlet

Arkon Iphone Waterproof Holder

Universal Vista Cruise Control

Cramp Buster

Utopia Back Rest

AMS Comfort Max Sheepskin Gel Pad Large

Rivco 7/8” Highway Peg mounts for GL1800

Rivco Anti Vibration Pegs Black Powder Coat

Givi Engine Guards

Givi Trekker Fog Lights

Givi Trekker 33 liter Saddlebags

Givi Trekker 54 liter Trunk

Givi Trekker truck and saddlebag mount

Koplin 1 ½ gal Fuel Pack Jr with Mount

¾ Square tube Homemade Gas tank mounts

2 Tooltubes mounted Inside Givi Racks

Honda Center Stand

H&B Skid plate

Interphone Head Set

Iphone

Awesome, thanks!!

 

[StratTuner]

As I recall, Honda specs an 11 lb limit for the frunk? (Do I remember that correctly?)

Now, if one pint weighs one pound ("a pint's a pound the world around." - my drunken sailor of a dad used to say)
then 8 pints = 1 US gallon. (Is that right?), then the frunk should only hold 1.25 gallons.

That buys you 1/3 more distance than you already have. Doesn't seem worth it to me.

I suppose if you want to ignore the 11lb limit, you could do a lot better, but that seems unwise.

 

[L.B.S.]

That buys you 1/3 more distance than you already have. Doesn't seem worth it to me.

I suppose if you want to ignore the 11lb limit, you could do a lot better, but that seems unwise.

Why on earth would it be not worth it?

I was out of fuel on my trip up to the North of Vancouver Island last week, as far away physically as one can go up there, (ie: no cell signal, no people, no gas stations, outer boondockia) and happily gurgled all of the 5 litres (1 1/4 US gal) into the NC's tank, and rode safely to my new destination.

I don't quite understand why people take some things as a 10 Commandments type of Thou Shalt Not!, when it comes to the most curious info label advice.

Not singling you out Strat, just mostly using your quote to post from.