Author Topic: Pillion Shelf and Fuel Cell ( ST1300 )  (Read 6148 times)

Offline KoTAOW

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Pillion Shelf and Fuel Cell ( ST1300 )
« on: May 18, 2008, 03:14:24 PM »
This article written by Curt Gran, STOC #5137, IBA# 330 and the original content is at this web page:

Pillion Shelf / Fuel Cell

Fabrication and Installation

I've been working on these two pieces for over a year now. I had the pillion shelf custom built and it worked great over the past year. Then I recently added the fuel cell. This setup is done according to the IBA restrictions meaning the that the total capacity carried does not exceed 11.5 gallons. The shelf mounts to the bike with brackets that were purchased separately. The fuel cell is a modified 4 gallon Summit Racing fuel cell. The shelf and the cell are mounted solid. The cell connects into the lower fuel tank using a fitting that I modified to screw into the inspection bolt hole on the lower tank (very convenient). The fuel cell hasn't had a full test yet so I'm hoping it does well come spring.

There isn't much of a how-to here but I'll cover some of the thought and design along with some of the pieces that were either manufactured or purchased.

Pillion Shelf Brackets

    * Frame mount brackets
    * Grab rail cover brackets

Contact and Price Information:

    * Roy Fletcher
    * Phone: 425-742-5995
    * Email:
    * Price: $100

Pillion Shelf

    * 3/16" aluminum stock
    * Steel support posts and feet
    * Hinges up for access to pillion seat
    * Allows removal of pillion seat

Fuel Cell (3.6 gallons)

    * 4 Gallon Summit Racing Fuel Cell
    * Cut down and new top welded on
    * Brackets welded to sides
    * Drain moved to rear corner of tank
    * Grounding block w/set screws added

Contact and Price Information:

    * Earache Motorsports
    * WebSite: Earache Motorsports
    * Price: ~$260 (fuel cell only)

Pillion Shelf and Brackets

  I found a pillion rack solution designed by the late Ron Smith and fabricated by Roy Fletcher. Ron's design is a tubular rack with a special mounting bracket for relocating a Honda top box over the pillion. Although it is a great design my purpose in installing a pillion shelf was for flat storage and eventually a fuel cell so the tubular rack and mounting bracket didn't exactly fit my needs. However the brackets that Roy fabricated to mount the shelf to the bike were exactly what I needed. I didn't see a need to reinvent them or make my own. Roy did take a bit of convincing but he eventually agreed to sell me just the brackets and I was very grateful. Thanks Roy.

  There are two sets of brackets and each is quite different. One set of brackets go under the pillion seat and bolt to the frame. The other set of smaller brackets bolt to two of the grab rail tail cover bolts. Both sets of brackets are pictured above. There are two bolts that are under the grab rail cover that bolt to the frame but none of the bolts on the grab rail cover bolt to the frame. So the back mounting point of the shelf which uses the smaller set of brackets and they are simply held in place by the front two bolts on the grab rail cover. This is still a very solid mount point and the hinge I had made was machined to exactly the width of the brackets so there is no movement once the shelf is mounted.

  The front brackets mount to the frame under the pillion shelf with one bolt through the bracket and the frame. The tough part is that you have to put a nut on the bolt between the rear fender and the frame which is a tight squeeze. I was able to put the one on the battery side of the bike without having to drop the rear fender but the fuse box (left) side wasn't as easy. I didn't have to remove the rear fender I just had to loosen it enough to drop it down a few inches and then get the bolt through and nut on. It wasn't hard but it did take some time to remove all the bolts to do it which include removing the bolts that hold the saddlebag locking brackets on to the frame. The pillion seat has small rubber feet on it that contact these front brackets that prevents the seat from sliding forward into the brackets that hold the front part of the pillion seat in place. I had to remove to bumpers from my Sargent seat in order to allow the pillion to seat into its retaining brackets. On the stock pillion seat I had to pop the front part of the bumper out and rotate it 180 degrees. It is only held by one of its retainers now but it works just fine.

  The other modification that needs to be done for the front brackets is to cut the side panels to allow the brackets to come out from underneath the seat. You can cut out a square notch or you can go for what I did which was to use a dremel and cut two slots to allow the brackets to go through. It does make it a little harder to take the side panels on and off but I just thought it would provide more support to the panel and also it just looks cleaner than notching the panel. It takes some patience to do this so take your time. Covering the paint with masking tape is a smart idea so you don't damage the area around the part you're trying to cut.

  Once the two sets of brackets were mounted I was able to mount the pillion shelf. The shelf was designed with a hinge plate at the back so that it swivels up after unscrewing two allen bolts. I use stainless steel button head allen bolts so they don't rust and have a smooth head that is easy on things that might rub against them. The front of the pillion shelf is supported by two steel rods that are threaded on the inside. Also a special set of feet were desinged out of steel to attach to the ends of the support rods that mate up with the frame brackets because the brackets sit at an angle that tilts forward when they are mounted on the bike. Allen bolts fasten the steel rods to the shelf and the feet. The feet fasten to the frame brackets also with allen bolts. When everything is bolted into place then shelf is very solid and I've actually lifted the bike off its side using the shelf as a handle. That's how solid it is.

Fuel Cell

  The fuel cell started out as a Summit Racing 4-Gallon aluminum fuel cell. $140 is less than you can buy the raw materials so it seemed like the best way to start. Since the tank is 4 gallons I needed to remove at least .2 gallons to get below the 11.5 gallons allowed by the IBA. From the dimensions of the top of the tank I calculated that removing 1" off the top of the tank would remove .4 gallons so we removed the one inch of height from the top of the tank and then welded on a new top. Two baffle plates were also added before the top was welded on to prevent sloshing.

  With a new top on the cell the holes were cut out for the filler cap. A hole was also drilled for a vent fitting. The old drain holes were plugged with aluminum caps that were machine to fit the old drain holes and then welded into place. Two more of these caps were made with made so that one could accommodate a fitting for the drain and the other for a vent fitting. A hole was drilled in the lower corner of the cell for the drain and one was put in the top corner for the vent. They were then tapped for the 1/8 NPT fittings and welded into place. To bolt the filler cap on I replaced the standard bolts with button head stainless steel allen bolts for a cleaner look and so they wouldn't rust.

  The tank came with mounting tabs which made mounting it to the pillion shelf easy. I used some nylon washers and some made from delron to raise the tank slightly because the mounting tabs were slightly higher than the base of the tank. This way the tank would not rub on the pillion shelf. Even with the washers the tank still mounts solid to the shelf. I wanted to be able to strap things to the side of the tank so we added a piece of u-channel on each side of the tank so that a strap could be run through it. This way a water bottle and possibly a cooler could be strapped to the sides. The last feature that we added was a small grounding block with two set screws added to it. This way two wires can be added for grounding purposes. One will go to the frame and another may go to the filler cap.

  The fittings on the tank are straight forward except for the fitting that is used to feed the fuel from the fuel cell into lower tank on the ST. The ST1300 has a an inspection bolt on the cover to the lower tank which makes for a perfect way to feed fuel into the lower tank without having to modify the tank. The inspection bolt can be removed safely with a T50 torque bit provided your fuel lever is below the top of the lower tank. After that I constructed a fitting to replace the bolt. I used a 90 degree fitting with 1/8" NPT threads and 1/4" hose barb on the other side. I then chased the threads to carefully change them to the matching metric threads of the inspection bolt. The fitting needed something to help seal the bolt whole so I tapped a brass washer with the same thread pattern and screwed it onto the fitting. I then added some JB Weld around the top to hold it in place and provide a little bit more of a seal. The inspection bolt has an o-ring underneath the flange head so I added an o-ring underneath the brass washer on the fitting that is designed for fuel applications.

  I screwed the fitting into the lower tank and aimed the hose barb so that it pointed in a direction that I could feed the tube out from between the driver and pillion seats. I then used a quick disconnect fitting, a filter, and a petcock in that order before it attaches to the drain fitting on the fuel cell. I keep the driver seat on the second position in the rear in order to allow the hose enough room to run through without being crushed or pinched. I purchased most of my fittings, the petcock, and quick disconnect from

  A couple of things that I may change are to relocate the drain to the bottom of the tank so that more fuel can drain out. As it is the fitting is about 1/2" above the bottom of the tank. Also the fuel filter may not be necessary on the line from the fuel cell to the lower tank since the there is already a filter in the lower tank on the ST. The last change would be to find a way to mount the petcock to the shelf just to secure it into place. Although I haven't had a full test of the fuel cell yet I believe it will suit my needs just fine.

  Ok I've put the whole cell together and mounted it. It has been tested and works very well. I'm including the detailed pictures of the final install below.

Thank You again for your contribution Curt Gran, STOC #5137, IBA# 330

« Last Edit: March 25, 2009, 08:42:23 PM by KoTAOW »