Harley Aux Tank

[lnelson]

I've been thinking about adding an auxiliary tank on my Harley Ultra Limited. The hardest part is hooking up the additional (new) gas line to the main tank or engine. If someone has accomplished that I would love to see some pictures and/or description on how to proceed?

 

[ScottAL]

I don't have the bike anymore so I can't show you a picture, but I ran the fuel line under the dash into a 90 degree bulkhead fitting drilled into the top plate to the right of the filler opening. Just about 3 o'clock if I remember correctly. It was a tight fit and only one spot it would go.

 

[BigLew55]

I don't have the bike anymore so I can't show you a picture, but I ran the fuel line under the dash into a 90 degree bulkhead fitting drilled into the top plate to the right of the filler opening. Just about 3 o'clock if I remember correctly. It was a tight fit and only one spot it would go.

This is precisely how mine is set up. Like Scott said, the location is fairly limited and dictated by the dimensions of the fitting and the landscape features of the top plate. It took me about 2 hours to get up the nerve to drill the first one. It only took about 15 minutes (of convincing myself) the second time...

I don't know anyone who has tapped into the fuel line on a fuel injected bike. That would require a bit of engineering with manifolds, check valves and switches. Maybe someone has and can add their experience here.

 

[Ira]

I'm not familiar with H-Ds, but I know on BMW fuel injected engines, it's common to tap into the fuel rail return line.

Ira

 

[BigLew55]

I'm not familiar with H-Ds, but I know on BMW fuel injected engines, it's common to tap into the fuel rail return line.

Ira

There's no return on the (current) Harley.

 

[Ira]

Scratch that idea.

 

[ScottAL]

About the only options on the HD touring bikes are the top plate or weld a bung on to the bottom of the tank. Some earlier models had a crossover pipe at the bottom front of the tank that was a good tee inlet but not the current touring lineup.

 

[Bill Burnside]

I've been thinking about adding an auxiliary tank on my Harley Ultra Limited. The hardest part is hooking up the additional (new) gas line to the main tank or engine. If someone has accomplished that I would love to see some pictures and/or description on how to proceed?

Hello Inelson
I have installed a aux tank on my 2017 ultra . The first time I wanted gravity flow. This was accomplished by installing a petcock behind the fuel supply line. The second one was done with a fuel pump plumbed into the top plate of the fuel sending unit at about 1 o’clock be careful to leave enough room between the support rib and your fitting to get a nut on . I will include some pics next time I pull the dash off

 

[lnelson]

Hello Inelson
I have installed a aux tank on my 2017 ultra . The first time I wanted gravity flow. This was accomplished by installing a petcock behind the fuel supply line. The second one was done with a fuel pump plumbed into the top plate of the fuel sending unit at about 1 o’clock be careful to leave enough room between the support rib and your fitting to get a nut on . I will include some pics next time I pull the dash off

Thanks that would be a great help.

 

[Bill Burnside]

Much apologies for not having a timely post . But it’s been a little nuts.

 

[lnelson]

Thank you, I’ve been to busy riding to get going on this, but this helps alot

 

[Bill Burnside]

Glad to help !! If you have any questions just reach out .

 

[streetglide15]

Much apologies for not having a timely post . But it’s been a little nuts. View attachment 5728

so you drilled a hole at 1oclock on sending unit and put an elbow in?. do you used a secondary 12v fuel pump plumbed into the inline you installed at 1oclock that pumps from the aux tank?

 

[Bill Burnside]

Correct , I installed a Holley fuel pump under my tour pack rack . I would run the main tank down to around a 1/4 tank then turn on the pump to fill the bike tank back up. This way I could use the fuel gauge to keep track of mileage.

 

[Tep_52]

For my 14 ultra classic I ripped the guts out of the vent and sealed the cap the aux tank then acts as the vent

 

[streetglide15]

Correct , I installed a Holley fuel pump under my tour pack rack . I would run the main tank down to around a 1/4 tank then turn on the pump to fill the bike tank back up. This way I could use the fuel gauge to keep track of mileage.

Makes sense... did you have the holley fuel pump hooked up to a toggle switch?. The 1 picture the bolt ? Was that when you unhooked the fuel line to run without the aux tank... sorry for all the questions... im looking to do this... wanna make sure on things... thanks for the reply

 

[Bill Burnside]

Yes ,I had it hooked to a toggle (pump) I had planned to hook that up to a timer at a latter date but I have since sold that bike. The bolt in the fuel line was a temporary fix till I got a quick connect. It’s a great thing to have a 350 mile range.

 

[streetglide15]

Yes ,I had it hooked to a toggle (pump) I had planned to hook that up to a timer at a latter date but I have since sold that bike. The bolt in the fuel line was a temporary fix till I got a quick connect. It’s a great thing to have a 350 mile range.

Bill did your holley pump need to have a check valve 1 way or could it free flow.. would a 4 to 7 psi pump be enough to push it to tank or should i go to like a 1w to15 psi.

 

[streetglide15]

Bill did your holley pump need to have a check valve 1 way or could it free flow.. would a 4 to 7 psi pump be enough to push it to tank or should i go to like a 1w to15 psi.

12 to 15 psi

 

[Bill Burnside]

No problem with the questions. I used the 4-7 psi pump. With no check valve. On the supply side I had a valve that was just below the toggle. Open valve turn pump on and watch the gas gauge climb. I used a fuel line for fuel injection just for a little more longevity.