Aux fuel tank mount on R1200RT

[cranezilla]

I am in the process of building and auxillary fuel tank mount for the R1200RT. Will be using a RCI 5 gallon fuel cell from Summit Racing, this fuel cell has been used for the last three years on my 89 FXR, upgraded the FXR to a 12 gallon unit in August, and now have an extra fuel cell perfect fit for the RT.

The fuel cell will mounts dwill be made to fit into the passenger seat brackets and be removable in the same fashion as the passenger seat, with the bike key, and a quick disconnect, the Harley has 3 bolts and a quick disconnect.

 

My question is;

What is the best method for attaching the fuel line to the R12RT's fuel tank, for gravity feed.

Will I need to drill an additional hole in the fuel tank and install the line using a bulkhead fitting or can the gravity feed fuel line be T'd into one of the vent lines?

This will give me a range of over 500 miles.

 

Was a simple matter on the Harley just T'd into the main fuel line at the carburetor.

 

Shut off valves used all around, have ridden over 100,000 miles on the Harley with this setup.

[BamaRider]

My question is this- the RT has huge tank and 300 miles of range, where ya goin to need all that gas or do ya hate to STOP that much to go through all this trouble to avoid it?

[cranezilla]

Deadhorse, Alaska for starters, the old Harley has been there twice.

 

2100 miles in under 30 hours again on the Harley.

 

1555 miles in 21 hours Harley again.

 

And not exceeding the speed limit by more than 10 miles per hour at anytime.

You can't do that stopping for gas every 90 miles.

 

Record so far on the R12RT is 850 miles in 14 hours. seat is too uncomforrtable, got another one ordered, stock seat on the Harley. Foot pegs replaced with foot boards better riding position for distance, Harley style highway pegs way more comfortable for distance.

 

Have been hearing for years how much more reliable and smoother the BMW's were.

 

Smoother, at highway speeds not too much difference.

More comfortable, not in stock configuration.

Reliable, 200,000 on the Harley 4,250 on the R12RT, this will take a while.

Handling, no comparison, BMW

Power, not even close, BMW.

Attention and recognition, my daughter didn't know that BMW made motocycles, but then she is only 32 and lived 3 blocks from the BMW dealer for 15 years, stopped in the Quick Trip next door to the dealer on her way to school everyday.

[cranezilla]

Check the attachment.

The red one has a 12 gallon fuel cell on the back, 16 gallon total capacity.

[BamaRider]

So why ya in a hurry all the time? Limited off time? Race?

[Buckster]

I would like to see photos of the fuel cell with seat brackets when you get it finished. This has been an idea I have been thinking of. Buckster

[DavidEBSmith]

If the 1200 is plumbed like the 1100 and the 1150, you can't just T into the vent line. The vent would come in at the top of the tank, so you'd need to have your aux tank mounted higher than the top of the main tank to get enough hydraulic head for fuel to flow. On the older bikes, the vent isn't just a vent, it has a doohickey on it that reduces the size of the vent opening to a pinhole - enough to let air in, but not enough to let a significant amount of fuel through.

 

If you want to use gravity feed, also forget about T-ing into the return line from the regulator to the fuel tank. There's enough pressure on the return line that you need a fuel pump to overcome it - gravity won't do it.

 

I can only recommend what I did on my RT. I installed a bulkhead fitting in the metal plate on the side of the tank that the fuel pump is mounted on. I thought about putting it into the plastic tank, but everybody I asked thought poorly of the idea. If you put a fitting in the plastic, you'd have to use a metal backing plate to have something secure for the fitting to mount to - the plastic of the tank is (at least on the older bikes) too flexible for a reliable seal.

 

I used all AN-6 hardware and hoses on my auxiliary tank. The good news is, that stuff is so big inside that the 3+ gallons from the aux tank drains into the main tank in about 10 minutes - it's faster than many setups with electric fuel pumps.

 

I know it probably doesn't matter, but you are aware that with a 5 gallon aux tank, you would be over the fuel capacity for any organized LD event (which is most of them) that follows the IBR rule of 11.5 gallons max. Just in case you ever want to enter an event with the bike.

[cranezilla]

Looks like the ideal spot is where the safety valve on the fuel tank is located.

 

The safety valve is a float operated vent valve that apperently goes to the charcoal canister.

 

To use this it will require modification of this valve, the addition of a second port to allow fuel input while retaining the float operated portion of the valve.

 

To do this I am going to buy another safety valve, cut it apart fabricate a new top plate with the two ports, one fuel input the other the vent vavle both will be Controlled by the original float.

 

If it don't work I just reinstall the original.