Author Topic: Aux. Fuel Tank Installation  (Read 5727 times)

Offline 4cedars

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Aux. Fuel Tank Installation
« on: January 11, 2012, 10:27:04 PM »
As promised last year after figuring out how to get the aux. tank flow problems figured out here is a run down on what I did to solve the issues.

After some brainstorming with a couple people on 2 different forums, this one and The MTF, it was decided that air had to be let out of the main tank in order to get the aux tank to flow. This is the option I chose, it may not be the option that the next person may choose and is definetely not an option if you have a weak stomach  :)or are going to fret and hand wring over warranty or other issues. I bought this motorcycle for 1 reason, to ride and do with as I please.

Now that that's out of the way lets go,

I looked at the install the late Davo Jones from down under documented on his 08 and was originally going to install the bulkhead fittings to the bottom of the tank next to the fuel pump like he did. Upon removal of my 10 tank I found ribs formed in the location where his was flat. So I opted for the back lower section of the tank. If doing it again I would move them up about a half to one inch for a little more clearance for the 90 degree elbows.

As you can see I used AN fittings in #8 size. Since this is a free flow system I wanted the best flow I could get. All the line I used is Parker 3/8 silicone push-loc hose. Very tough even to cut with a razor knife.

The white line inside the tank is the air line coming from the aux tank and is the heart of this system. It is a piece of 1/2" PTFE tubing. I had a fitting swaged onto the end at the local hydraulic hose shop. I went with the 90 on the end to stay as tight to the tank as I could for fuel gage clearance. The length was trial and error.I ordered 3 feet and ended up using about 2'6". The routing of this hose is extremely important. If not located correctly it will obstruct the movement of the fuel gage. Mine will not quite reach the full location. Maybe a smaller tube would be easier to manipulate and get clearance with, but this works. I am not as concerned with showing full as I am showing empty accurately.  It must go under the metal lines welded in the tank. It then curves around a bracket and ends next to the recess for the filler cap. This is where I figured there was the least chance for getting fuel into the line and obstructing air flow. You can not see it in the photos but it is sprung into the final location and "should" never come out of there. To get the bend in the tubing I heated it slowly with a propane torch and kept working it until I had something to work with and was able to thread it around where I wanted it to go.

The cable tie behind the nut of the air line is to keep the nut from pushing back while getting the bulkhead fitting threaded into it. This proved to be the hardest part of the whole project unless you have child-like hands. I ended up making a special "wrench" to get in the tank and tighten the nut on the bulkhead fitting after the air line was threaded onto it.

The crossed lines are necessary for hose routing in the limited space behind the tank and in front of the shield for the rear tire.

I used a hole saw and removed some plastic for the hose locations after experimenting with different hose paths.

The tank is a off the shelf foam filled JAZ unit I got online. It is supposed to be 4 gallon but only holds about 3.25. It is mounted to a aluminum rack I built myself to the dimensions of the tank. I had to move the hole on top of the tank to place it in a better location for my needs. Mounted on the bike in this manner it has a slight forward tilt to it, putting the overflow and air line in fuel if you overfill even slightly. Moving it back solved this problem. The tank comes with 4 holes in it so I plugged 3 and used 1 along with the 1 I drilled.

On the top of the tank is a T-fitting with a straight hose connector going to the overflow line on the left side of the bike and on the rear of the T is a 180 fitting I purposely left in the up position. This goes the the air line in the tank. I have it elevated so any fuel that comes into the T will go out the overflow and not into the airline. Getting fuel in this line should be avoided at all costs as it will block the airflow and not allow the aux tank to empty. EXPERIENCE ;) If it does happen just undo the airline fitting and blow the fuel out of it. Also, use caution to avoid dumping your load before it will all fit in the main. You can easily overfill the main and get fuel into the airline. Again,EXPERIENCE :banghead:

Remember to run a ground wire from the filler ring to the bike and put the overflow on the left side. Otherwise you may be in for some interesting pyrotechnics 8)

Don"t ask about costs, trust me :'(         John


The aux tank flows out to a brass valve I got at the hardware store into a stainless steel screen filter (Jegs) then a quick disconnect and into the main tank. I can reach back, grab the handle and pull it forward to dump the load.
IBA# 45862
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Offline 4cedars

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Re: Aux. Fuel Tank Installation
« Reply #1 on: January 11, 2012, 10:29:20 PM »
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IBA# 45862
MTF Tourers Assistant
2012 Tour of Honor State Sponsor (IL)
2013 Tour of Honor State Sponsor (IL and IN)

Offline 4cedars

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Re: Aux. Fuel Tank Installation
« Reply #2 on: January 11, 2012, 10:30:19 PM »
Last Ones
IBA# 45862
MTF Tourers Assistant
2012 Tour of Honor State Sponsor (IL)
2013 Tour of Honor State Sponsor (IL and IN)

Offline Rhino

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Re: Aux. Fuel Tank Installation
« Reply #3 on: January 12, 2012, 09:30:15 AM »
Nice engineering. That is hard core. I admit I always wanted more range on my Valkyrie, I had to start looking for gas at 100 miles and at 135 I'd be out. For riding in the continental US the C14 seems to have plenty of range for me. If I was planning a trip to Tierra Del Fuego I'd be all over a mod like this.