R1100RT Aux Tank Build

We got lucky and had a valve with a long handle. This was a really snug fit and took a couple of hours to figure out how and where.

Our equipment identification tag with model number, serial number, and date of mfg.

Rear mount with SS ball lock pins with retaining lanyards.

The finished product mounted and ready to roll. Note vent line with air filter.

Detail view of the drain, shock mounts, and latch tab. And the paint job as well.

Done and under pressure. We watch it for at least 12 hours at 4psi to make sure there aren't any pinholes. After pressure testing it will go for powder coating and more pictures will be added detailing the finished product.

With the deck.

Sitting in place.

Bottom view.

Left side view.

Here is the finished product as viewed from the right side.

Notice that the front plate has a machined pocket for the rider seat bracket. It turns out that the way this base plate set in after it was finished put the front at the wrong angle. It was quite a challenge getting this base into the milling machine to get the proper angle.

Everything is disassembled ready to fabricate and weld the sides on.

The slot you see at the bottom of the support bar is for a rubber grommet to provide vibration isolation. These were removed since we've been welding on this sfuff.

Down rods were fabricated and welded to the deck rails for attachment at the rear.

With some diligent internet searching we found these stainless steel ball lock pins. These puppies are EXPENSIVE!! Like $50 each normally. I got these off of ebay and pass the savings on. :-)

The selected design is this stainless steel bracket that is sandwiched in the stock luggage rack mounting points. This is a frame hard point and will certainly fill the bill on being secure.

Now that the mount and tank are designed and fabricated the remaining items are locating the drain (the shut off valve has to be reachable and clear everything), and the rear mount needs to be designed and fabricated.

Here is the cell with the top, baffle, and deck mounting rails welded in place.

The inside of the tank was welded at the front.

Here you can see the cell in relation to the stock tank, Plenty of height for gravity feed and it looks like it might even be below the top of the stock tank.

Here is the gap over the stock luggage rack. Looks like a good place to put a glove box or tool storage.

Exactly 6.5 inches with the seat in the uppermost position.

This is with the deck sitting as it will be mounted.

This is how far back the tank extends.

Once the final dimensions were established the shell of the tank was bent up.

With the seat in the uppermost position the front of the cell had to move back. This changed the capacity quite a bit and other dimensions had to be modified to maintain the target capacity.

The initial design was done with the seat in the lowest position (how it was received). I didn't pay enough attention that the seat has 3 positions. Luckily this was discovered before the tank was constructed becase the seat moves up and BACK! Here is the uppermost position.

Detail of shock rest

detail of latching mechanism

Bracket in position wth rider seat in upmost position.

Close view of the front with the rider seat retaining bracket.

Here is the completed rear of the mount. Finding those screw in rubber feet was quite a challenge. Here you see the blocks at rear provide shock mounting and sit in same position as pillion seat bumpers and the SS bracket which engages the pillion seat locking mechanism.

The solution was to get that precise angle and then machine some blocks which would rest on the frame.

Mounting bracket base. Uses hardware scavenged from pillion seat.

Once the base mount was fabricated the next challenge was to figure out how to support it at the rear. The pillion seat rests on rubber bumpers where the plastic turns up just behind the bolt in the lower right of the photo. We need to copy that somehow.

Ready to mount the latch tab at the rear.

Determining how to get the front and rear plates in the proper position took a LONG time.

This is the latch tab on the rear plate.

Forward end of mounting system. Uses the pillion seat brackets which slide in to pockets.

Here are the machined plates to be used for the front and rear of the mount.

and again,

Just another view of how it will appear.

The luggage deck was put in position to see how it was going to look. From this view it was obvious that some type of rear mount was going to be needed, This rear mount had to support the weight of any luggage and it had to securely retain the cell. You can tell that with any weight on this deck, the moment of inertia would rip the rear seat latch out of its mounting.

This was put into place and measurements were taken again to make final adjustments.

Armed with this information we bent up some scrap aluminum to with the angles and dimensions.

Next was to determine the angle and position of the rear of the cell. Here we have placed some PVC foam board aligned with the latch tab and then got the angle and distances.

Seat latch tabs mounted on model plate.

Detail of front tab.

Here is the model for the front mount.

Model made out of scrap aluminum pieces and PVC foam board. It cuts nicely and can be machined.

Ripping up the pillion seat to canabalize the hardware.

Much thought and planning goes into the project. Measure twice and cut once.

The hard part of building a cell is figuring out how to mount it. With this bike it wasn't simply a matter of removing the pillion seat and going from there. The pillion seat latches and holds the rider seat in position. We determined that the cell mount would have to mimic the pillion seat mount. Towards that end we copied the design and used the hardware from the pillion seat. [NOTE the cute little sheet metal bender mounted in my vise. This is great for making thin gauge models.]

Hours later it still won't take a charge. It seems that months in storage with the drain of a couple of LEDs completely ruined this battery.

Battery charger finally connected.

Battery was deader than a doornail. What a PITA to get to the positive terminal. It took a google search to find the answer. Either remove the left side for access to the starter motor or the right side for access to the post! I'd sure hate to have this problem in the middle of a timed rally.

Unloading the bike.

Unpacking the bike.

Truck pulling up for delivery.

Right rear view.

The process of building a cell and getting it mounted literally takes hundreds of trips to the drawing board. Thank goodness for CAD. Here you see the left front view of the design I ended up with. It didn't start here but you'll see that the finished product matches the plan. I use CREO Elements free version and find it to be robust enough to suite my needs. The cool thing is getting the exact volume of the tank before you ever cut a part.

Off to fill 'er up and give it a test ride.