Aux Tank on '22 Tiger 900

Jerry L. Stevens

Jerry L. Stevens

Premier Member
#1
#1
I downsized to the 2022 Tiger 900. One reason at age 74 my RSV was becoming a beast and getting long in the tooth. Second reason I plan to ride the Trans Labrador Highway this summer so this type of motorcycle would be a better fit. BMW 1250 and Tiger 1200 were out of my price range at present.

I don't like the seat or the chain but I will adapt. The seat has been reworked and I installed a Scott Oiler for the chain. Seems to be working fine.

Now to the point:
My last two motorcycles were carburetor equipped. I had aux fuel tanks on them. They have taken me on many IBA rides, 49 states, and all Canadian provinces/territories with roads. Since both were carburetor equipped, gravity feed worked great. However, I am new to the FI motorcycle world with 2022 emissions requirements.

I have decided to go with my 3 gallon (or maybe the 5 gallon) tank mounted on the pillion. I plan to use the vent hose to feed fuel from the aux to the main as per several of you have done. I understand the fueling process, main first then close, it then fill aux.

My question is since the charcoal canister valve is controlled by the ECU will a code be thrown if I disconnect the vent line on the tank side from the valve to use it for my aux feed? I thought I'd just cap the valve.

For now I am not concerned about the legality of disconnecting the cannister. I can deal with that after I have the aux tank plumbed. One thing at a time.
 
Marc11

Marc11

Premier Member
IBR Finisher
#2
#2
A code should not be thrown if you disconnect the vent line as long as you ensure the old vent line is unobstructed, don't cap the valve. When the purge valve opens is just movies air through the vent hose, it doesn't know if that air is from the tank or not.

I would suggest running your aux tank line to the tank vent and direct connect, the vent line from the canister is often soft, easily kinked and prone to sharp turns which may cause fuel flow issues. Just my opinion, some of used that line without issue so YMMV.

I've done this aux feed method on two BMWs a 2017 and 2021, neither have had a code thrown, nor have I heard of any other bike/brand having that issue.
 
Russ Black

Russ Black

Premier Member
#3
#3
I've done both methods. The Gravity method is connecting the Aux tank to the main tank through it's vent. I extended and plumbed the bikes vent hose back to the aux tank. A valve between the two tanks is not necessary to make it work, but I installed a valve mainly so I could remove the aux tank with fuel still in it if I needed to. That is the only time you really need to use that valve. Fill the main tank first, close the cap and then the Aux. That is all there is to it. As the fuel is consumed in the main tank, it is replaced oz for oz from the aux tank, keepig the main tank full until the fuel in the aux tank is exhausted. Now the fuel level in the main tank will lower as usual before the aux tank was installed. The bikes fuel gauge will show full until the aux tank becomes empty and then the fuel gauge will act as normal once the aux tank is empty. The only problem I ever had using this method is during the summer when the air temp was 90F and above. The heat causes the fuel to evaporate a bit which pressurized the tank and not allowing the fuel to flow from the Aux tank and the air to the Aux tank until the main tank was almost empty and the pressure equalized. I was using 1/4" fuel line and I had a dip of several inches below where the vent went into the main tank. Perhaps a larger hose or less dip would work better. My usual fix was to open the fuel cap for a moment at the next stop (traffic light or bonus location) to allow the fuel to flow again.

I have also used a pump to get the fuel from the Aux tank into the main tank using the fuel return line. The vent is untouched. This is where you must have a valve between the two tanks. The valve must be shut when fueling and remain shut until which time you start transferring fuel. You can fill the two tanks in either order. You first use the fuel out of the main tank down to a level that will allow you to transfer the entire contents of the Aux into the main tank without overfilling it. You do this by opening the valve between them and turning on the pump. Usually both the valve and switch for the pump are going to be behind you requiring you to operate them by feel. The gravity method does not as the valve can remain open. I suggest timing how long it takes for the fuel to transfer with the engine running. The fuel return line is pressurized and this slows the flow as the pump has to work harder to overcome it. I have a very inexpensive low pressure pump and at highway speed it takes about 35 minutes to transfer 4.5 gallons. Tank size, fuel line size, type of pump, fuel return line pressure will all effect the transfer time. Using the pump method your fuel gauge works as normal until you start transferring fuel from the Aux tank. It is quite satisfying to see the tank getting fuller as you drive. Too bad it's not true. It will work as normal once all the fuel is transferred.

No Codes and the bike ran fine.
 
Marc11

Marc11

Premier Member
IBR Finisher
#5
#5
Jerry L. Stevens said:
Thanks Russ
I'll use the vent method with QD. I have 3/16ths outlet on my aux tank with 3/16ths fuel line.
Click to expand...
Be careful, if you use the QD to disconnect the aux tank using the vent method you'll effectively block your tank from venting as the QD will shut off all air and fuel flow from both ends.
 
Jerry L. Stevens

Jerry L. Stevens

Premier Member
#6
#6
Thanks for the reminder, Marc. Oh yes, I just meant the QD on the aux side. Then QD connect a vent line so tank will still vent.

The IBA family is great. I knew I'd get reliable info here. On many forums when a person mentions aux tank, responses are like a lecture from a school marm as to why any person would want or need to go more than a tank.

They just don't get it. Of course, when they call 300 miles a long day what should I expect?
 
Marc11

Marc11

Premier Member
IBR Finisher
#7
#7
Jerry L. Stevens said:
Thanks for the reminder, Marc. Oh yes, I just meant the QD on the aux side. Then QD connect a vent line so tank will still vent.

The IBA family is great. I knew I'd get reliable info here. On many forums when a person mentions aux tank, responses are like a lecture from a school marm as to why any person would want or need to go more than a tank.

They just don't get it. Of course, when they call 300 miles a long day what should I expect?
Click to expand...
Yep I gave up discussing LD riding topics on general forums, don't need lectures from someone who has no clue what they are talking about but bought a soapbox to stand on.
 
R3Tex

R3Tex

Premier Member
#9
#9
Not sure about the Tiger 900, but my 2017 Tiger Explorer has a balance line that runs between the two sides of the front of the tank. This is where I tied my Aux Fuel line in and it has worked great for several thousand miles. Cutting the balance line and putting a Tee in place was pretty easy and the factory vent lines stays dedicated to that purpose. Just a thought.
 
Terrywerm

Terrywerm

Active Member
#11
#11
When a QD (quick disconnect) is mentioned, what sort of connector are you using? The only thing that comes to mind for me is a QD for an outboard motor, which I suspect will work just fine, but I wanted to ask just in case there is something else that works just as well or maybe even better.

Great topic, these are the kind of discussions that keep me coming back. I agree with previous posts about having some of these discussions on other forums. Those who are over-opinionated always have something to say even if it is worthless information. I swear that some of those people would argue against the statement "the sky is blue" just so they could get on their soapbox and preach to the masses. Anyway, I digress...
 
c10

c10

Well-Known Member
#17
#17
The 900 Tank does not have a linked fuel line like the older Gen 1, 2, 3 Tex 1200 model . that connect the two sides , and runs down to the low portion for tank draining to remove for services .
I own bot a 900GT , and a 1200XCX . What is pretty neat is both get nearly same mpg at fill ups . If you take two teeth of rear or add 1 tooth up front you will add a few miles per gallon .
 
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