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darryl
06-07-2012, 06:30 PM
I want to add to the fuel capacity on my motorcycle. I'm playing with the idea of removing the existing storage bags and building an entire one-piece rear section in fiberglass which would include the rear passenger back rest. I want to include a small gas tank on each side, probably on the inside closest to the tire for the best protection that's possible. My storage for gloves, rainsuit, etc, would be in sort of a half-donut shape surrounding the tanks and going around the back. I'm not worried about the lights as that can all be re-done. Where the mufflers pass under the structure, I would include a stainless steel heat deflector to keep as much of the heat as possible from wafting up into the fiberglass.

Anyway, this is not so much about how I design and build this- it's more about what can I use for the tanks. I don't want anything wide or long, as that gives rise to fuel sloshing around. I'm thinking that four two-litre plastic juice bottles would be enough capacity- that would be two per side, and each would be plumbed in and vented from the top. No holes made in the bottoms- fuel flow would be gravity fed and require priming of the tubing. It looks like I can have the bottoms of the tanks a little above the carbs when the bike is level, so it should all work out.

I'm planning to encapsulate the juice bottles in spray foam so they are protected from impact all around, and the upper area where the caps are would be formed so that any spilled fuel would be channeled away.

I'm mostly concerned about the tanks- what material SHOULD they be made from? Obviously I want well-fitted caps, not the leak-prone ones that seem to be common on those plastic gas cans. The caps on these juice bottles always seal well, and are large enough for a filler nozzle to go into (I think- I will have to make sure of this). Also, the juice bottle being clear it gives a way to see how full it's getting as you fill it.

I could have the tanks custom made, but unless they are properly done they would be prone to developing leaks over time. This is still an option though. Another option is to find some 1 gal plastic gas cans and make a molded-in area for them to fit into. They would then be removed to be filled, and would not be plumbed in at all. They would be removed to pour the contents into the existing tank.

Ideas?

ckelloug
06-07-2012, 07:03 PM
Gas cans sound like a much better idea. Gas cans have the advantage that in the unmodified condition, they are considered by authorities as appropriate for transporting gasoline.

darryl
06-07-2012, 07:19 PM
That's a good point. There does seem to be some confusion (in my mind anyway) about DOT approved containers. There was mention on at least one site I went to that plastic gas cans are not DOT approved- what would that mean- that you can't transport them to a filling station?

DOT approval is one thing- 'considered by authorities' is another, incontroversial by insurance agents would be another.

Obviously any container which I make or have made is not going to have the DOT stamp of approval, though it might pass the specifications test.

In any event, I'm thinking my best bet would be to use a 'regulation' container and make a nest for it in my construction. At least it has the other advantage of being able to refuel another bike as well as my own.

sasquatch
06-07-2012, 08:33 PM
Darryl, you have a good idea there, but as stated, i'd think using regulation fuel cans would be much better , and certainly would eliminate any hassles with insurance etc.
In Ontario it is illegal for a station attendant to fill anything with gasoline other than a regulation can. I think they sell those red plastic gas cans @ 2 gallon size, don't think i've seen any smaller.

Hmmm, if you do want something else, what about some of the plastic lawn mower tanks, think the cap also has a gauge on some i've seen?
I was thinking of a nice say 4-6inch dia. brass tube soldered up ends and a nice soldered in gas cap?
Interesting project anyway.:D

darryl
06-07-2012, 09:43 PM
The project will be interesting. This is for my 400 Honda. I want to still be able to ride it while the fabrication is going on, so I'll have to strip it just enough to get the information to build the mold from. That's basically for mounting points, width of the fender over the tire, etc. I'll be changing the tail lights to leds, and those could be incorporated within the fabrication.

If I can mold the inner part right on the bike frame, that will get me a really good fit for this fabrication. I'll add some mold parts which will get stripped away later- these would be for the inner walls. With an edge added all around this, I should have a fabrication which can be removed from the bike and finished up separately. I know I'll have to do lots of smoothing before the color gel coat, but that's just how it goes if you don't make a full female mold first. Lots of fun.

flylo
06-07-2012, 09:48 PM
Don't remember on what but I've seen the frame itself or major portions used as a fuel tank. Beats holding air. I had a Rokon 2WD motorcycle that had 2-4.5 gallon wheels to store fuel.
Would the main backbone of the frame work?

sasquatch
06-07-2012, 09:52 PM
I saw one of those Rokon bikes in the back of a pickup a few years ago. Looked like someone had restored it. I was amazed when i researched that name and found out about the fuel in the rims!!:eek:

They gotta be worth a few bucks??

darryl
06-07-2012, 10:06 PM
Fuel in the rims? I can see the frame being used to store fuel, or even built with large diameter tubing for the purpose-

flathead4
06-07-2012, 10:13 PM
I'm mostly concerned about the tanks- what material SHOULD they be made from?

What material ARE street motorcycle gas tanks made of? I haven't paid much attention to bikes since I sold my old Triumph back in '80, but aren't most, if not all, street bike tanks made of metal (steel?). Being a crash survivor, I would not want to hit the ground with a plastic tank anywhere on board. Sounds like an opportunity to hone your welding skills. You could build a custom, even removable, tank that fits your bike.

Tom

SteveF
06-07-2012, 10:33 PM
Well, if I was looking for fuel capacity, my first choice would be:

http://www.amazon.com/Reda-Portable-Motorcycle-Gas-Can/dp/B003WHBVDI


If I was looking for fuel capacity and a project, I would make a new gas tank that is larger than the stock tank. Takes care of all the plumbing and venting issues. Plus you get to pound on sheet metal with a hammer!! Plus your bike is fully operational while you make the new tank once you get the mounting measurements off the existing tank.

Steve

CCWKen
06-07-2012, 10:42 PM
Is this going to be for re-fueling the stock tank or do you plan on drawing fuel from the tank(s)? If it's below the carb, you'll need a low-pre$$ure fuel pump. Also consider the extra weight. You might be better off adapting a stock tank from a larger bike or expanding the existing tank. You could always keep riding while another tank is being modified.

I rode my Honda Gold Wing Interstate from Ohio to Texas (round trip) on several occasions. Toward the end of the trip, I was pretty much looking forward to the gas stops. :o I drove straight through on each trip and even with the stops, I averaged about 60mph over the 1400 mile legs. Don't know if I could handle that now being 30 years older. :rolleyes:

SteveF
06-07-2012, 10:58 PM
You might be better off adapting a stock tank from a larger bike or expanding the existing tank. You could always keep riding while another tank is being modified.


There's an idea. Darryl - how big is the existing tank?

Steve

darryl
06-08-2012, 01:21 AM
A bigger main tank- it would have to be wider or taller. I wouldn't want wider, but taller could be an option. I don't really think I'd want to change the existing tank, though. Plus, I don't think it's in me to 'pound up' a new sheet metal tank.

My existing tank is 3.7 gallons which gives me up to about 300 miles- I have run out on trips, and that's no fun. To have some extra fuel on board is just good insurance, since if I happen to be on reserve already and forgotten about it- well that has happened more than once. Besides that, I don't like the feeling of riding while hoping I make it to the next station- been there too many times too.

I could go either way with the fuel feed- plumb it in or just pour the fuel from the spare can into the tank when I'm getting low. I'm leaning towards the latter since then I can fuel my riding partner if need be, and they can avoid the same 'hope I make it' syndrome too. Two gallons would give me an extra 150 miles, or two of us about 60 miles.

jep24601
06-08-2012, 09:52 AM
Soldered copper makes good gas tanks. A friend of mine got a very nice replica made by an artisan in Katmandu.

oldwing
06-08-2012, 10:27 AM
You know, the guys who do 1,000 miles a day. Check out what they do:

http://www.ldriders.com/fuel-cells.html

Black_Moons
06-08-2012, 10:43 AM
Id just buy some of those $7 1 gallon jerry cans and strap those to the side.

As far as 'approved gasoline container', if its attached to your motorbike, Doesnt anything qualify then? Else no homebuilt car/motor bike could ever be filled up.

George Bulliss
06-08-2012, 10:49 AM
Id look into the kind of fuel bottles backpackers use to carry white gas. They are usually made from stainless steel, have good sealing lids and can handle the pressures caused from heating. Might be a pricey way to go, depending on how big they are and how many you would need.

George

SteveF
06-08-2012, 10:55 AM
To have some extra fuel on board is just good insurance, since if I happen to be on reserve already and forgotten about it- well that has happened more than once. Besides that, I don't like the feeling of riding while hoping I make it to the next station- been there too many times too.


Can't really help with running around with the fuel selector set to Reserve until it's empty. ;) Maybe a microswitch on the fuel selector connected to a red LED above the speedo?

Don't know about the density of gas stations where you ride but I don't worry about making it to the next one with my GPS. Just hit the Fuel menu button and it tells me where and how far. Definitely removes the stress of that issue when the tank is getting low.

Steve

rowbare
06-08-2012, 11:29 AM
I think a replacement tank is your best bet. The tank location is about the best protected spot on a bike. I would be wary of having tanks at the unprotected extremities of a bike.

bob

EVguru
06-08-2012, 12:49 PM
Soldered copper makes good gas tanks. A friend of mine got a very nice replica made by an artisan in Katmandu.

No, it makes tanks that are prone to cracking and leaking. Both copper and lead solder are prone to fatigue from flex and vibration. Ask anyone who actually uses a Brough Superior!

Tanks are usually made from welded Steel or Aluminium, Fibreglass, or moulded thermo-plastic. The latter two can be problematic with modern fuel formulations. Plastic tanks were banned for a long time in the UK after there were problems with fibreglass tanks leaking or even splitting. I've had problems with thermo-plastic tanks leaking around the fuel outlet.

Welded tanks would be my choice. Internal baffles or even better open cell tank foam takes care of surge problems. There are vacuum operated pulse pumps that can be run from an inlet manifold tapping than would deal with transfer issues.

jep24601
06-08-2012, 01:37 PM
Id look into the kind of fuel bottles backpackers use to carry white gas. They are usually made from stainless steel, have good sealing lids and can handle the pressures caused from heating. Might be a pricey way to go, depending on how big they are and how many you would need.

George
That's what I carry for a little spare fuel in case I run out.

J Weber
06-09-2012, 09:32 AM
Read about a guy that made a cycle tank out of epoxy rosin/glass over a Styrofoam mold.Used gas or acetone to melt out foam.Then used one of the rubber gas tank products to coat the inside.Interesting way to build one.

flylo
06-09-2012, 11:00 AM
You know, the guys who do 1,000 miles a day. Check out what they do:

http://www.ldriders.com/fuel-cells.html


My son & I did an Ironbutt (1000 miles in a day),we rode 1275, then I found out a guy did it on a Yamaha 70 LOL!

darryl
06-09-2012, 08:54 PM
On one of my last road trips with a friend, we did 35 miles the first day, 77 miles the second day, and a whopping 200 or so the next day. I'm going for the record- least number of highway miles traveled per day on a motorcycle :)

CCWKen
06-09-2012, 10:31 PM
A bigger main tank- it would have to be wider or taller. I wouldn't want wider, but taller could be an option. I don't really think I'd want to change the existing tank, though. Plus, I don't think it's in me to 'pound up' a new sheet metal tank.

My existing tank is 3.7 gallons which gives me up to about 300 miles- I have run out on trips, and that's no fun. To have some extra fuel on board is just good insurance, since if I happen to be on reserve already and forgotten about it- well that has happened more than once. Besides that, I don't like the feeling of riding while hoping I make it to the next station- been there too many times too.

Well, you can't make it idiot proof. Reserve is reserve. I suppose you could even forget to refill your carry-on too. Smart riders (and drivers) start planing for a fuel stop when the needle hits 1/3-1/4. :rolleyes:

I meant that you could buy a used tank and modify it while still using the original. Better yet, have someone else do it since apparently you can't handle it. Adding about 2" to the height would probably double your capacity; maybe more--I'm not familiar with the small bike tanks. Just keep in mind that 144 cubic inches (one cubic foot) will hold almost 7.5 gallons.