Auxillary Fuel Tank

[John]

Here's some pics of the aux tank mock up that I just made. I filled it with sand to get an idea of how much capacity it would have, but I only had 1.5 gals of sand , and that only filled it to about 3/4 full, so I figure it will hold 2 gals or better. I plan on mounting it under my luggage rack. Any comments/suggestions?
Thanks guys.

[John]

I also just won a final drive from an XS 850 on ebay, so I'll be doing that conversion soon. Currently, I get about 30 mpg at freeway speed, so I'm hoping to get about 35 mpg or better, and with over 5 gals of fuel capacity, I should be able to get about 175 miles per fill up. My ass won't last that long, but my fuel will.

[DiverRay]

John,
Don't forget to "mock" the fuel fill and the output/petcock. I would probably have the fill come off one side, and put the outlet low on the same side. Think outboard cap, with the vent that can be closed, for "long term" storage without gas smells in the garage.
Just my 2 cents....
Ray

[Dragonrider]

Cool! Weld carefully! Fuel will find it's way through any defects.

Pondering doing the same for my Valk...they make a bellytank for it, but I'd have to lose my center stand (not willing to). Thinking about making my own bellytank with tabs for the centerstand integral to the tank...

[Erik the Red]

fuel fill location

You've probably already thought of this but...

I don't know what kind of luggage setup you ride with, but make sure that you can fill the tank even with your bike loaded up with all your luggage that'll be sitting right above (and to the sides).

Also, how will it be for rear tire maintenance? Easy on, easy off tank?

[81xsproject]

my first thought is the elevation. Will it be high enought to gravity feed? Or, are you going to have a pump to deliver it to the main tank? That combined with the taller final drive ration should give you some SERIOUS distance

[Yamaniac]

Not to discount what you have done John, as I have thought about doing something similar, and your design looks good.. but..

Have you looked into having your regular tank enlarged? First, let me say that I don't know if it would be cost effective to do so. I have pondered if that wouldn't be a better long term solution. I like the design of my special tank, but wouldn't be opposed to widening it an inch or so on each side, flattening out the bottom edge, and even raising the top of the tank. If I could get another 2+ gallon out of that, and it was cost effective, I'd be a happy camper.

Just some random thoughts...

Theron

[Yamaniac]

okay, just saw other post where you have a bunch of tanks and have already thought of that (my previous post)

[Pat Kelly]

My concern is a (in my opinion) flaw with the bike.

Push down on your rack/trunk, notice it moves? Everything behind the shock mounts is just hanging there. There's nothing to support that weight, even a rack designed for the XS is just extending the unsupported frame past the shocks. Even a passenger's weight is flexing the frame at the shock mounts. Wonder why some people have their frame break there?

I have been thinking of fabricating some struts fro the rearward portion of the rack down to the mounting plates of the saddlebags. That would help. I just haven't fount the right strut material, yet.

[John]

Thanks for the suggestions guys. I have already given some thought to the filler neck, and pick up tube. The tube will be placed right above the curved area that conforms to the fender. That area is right behind the seat. I can weld in a bung, and run the tube down into the low area of the sump. I want to find a small, gasoline approved pump that will fit in the space occupied by the tool box, or just remove the tool box, and mount the pump in there some where. The filler neck will probably be on the right side, so the fill port will be on the high side, like the fuel cap is on the stock fuel tank. After the welding is done I may use a fuel tank liner kit just to be sure it has no leaks. I want to have as few seams as possible, so I will unfold the tank, like opening up a cardbord box and, make as many bends on a bending break as I can.The entire top, sides, and ends can be one piece of 20 gauge sheet metal. The bottom section can also be one piece. I'll just need to form the curved area over a piece of large diameter pipe
As far as the weight goes, two gallons of gas is roughly 12 lbs. Not much more that a 12 pack. When I do carry a load, a lot of the weight is borne by the rear of the seat, as my back rest is always adjusted forward. The front of the rack is attached at the upper shock mounts, and there is another support strut that attaches to the rear of the frame.
Here is a pretty good pic of the rack. You can see how it is supported. When the bike is on the centerstand I can push down on the back of the rack, raise the front tire, and pivot it on the centerstand, so I'm not too concerned with any flexing.

Click on the pic to see it full size.
As far as it being in the way of any maintenence, it will not interfere with anything at all. Tire removal is done with out having to remove the fender. I had an XS750 SF before the 11, and the rear fender was hinged to facilitate tire removal, but that is not the case with the 11.
I recieved my 850 final drive today, so when I go back to work Saturday, I will follow Maximam's installation tips, and have it ready for my possible trip to Houston on Thanksgiving weekend to participate in the farewell ride to Pathfinder's (Planedick's new) bike. It looks like WK and I will be sharing the riding duties. WK's brother lives in the Houston area, so we may be able to spend Friday night there, or we may find a hotel in Cynthia's area, as she lives on the opposite side of town as my BIL, and it looks to be about 50 miles or so between the two locations. BIL lives in Friendswood, on the SE side of Houston, and Cynthia is on the NW side of town. We will be bringing the bike and a car, as my butt can't handle that many miles in the saddle. I may ride the first and last 100 miles, and WK will ride the second 100 miles, and reverse that on the return trip to D/FW. I don't think the aux tank will be done by then, but ya never know.

[DiverRay]

John,
There used to be a universal fuel pump that would fit almost anything. it was a small square shape, about 3" on a side. I think they may still be around, so ask at the parts store.
I did forget the pilot box this past summer, so I guess I'll have you send it back sometime in the next three months.
Ray

[trukleon]

amount

length times width times heith , divided by 232 (all in inches will five you you a very close amount.. Just my two cents (check it with a jerry can if you like).

[trukleon]

whoops

Hope Burly1 doesn't read this.

[HobbyMan]

I know that it has been mentioned before, but make sure it won't crack the frame. I would also wonder about the Cg difference from having the extra mass behind the rear wheel. If it works out, this would be a really cool mod. If you want a really long range, how about a fuel trailer Maby instead of saddle bags, some fuel tanks, that would also be really cool.

[trukleon]

petcock

Might want to look into something like this,http://www.afcvalves.com/ retrieved off of xs 750 sight..