I’ve not run out of gas, but have cut it close a time or two on various bikes. The GS has a wide range of gas mileage depending upon the environment and the amount of wrist twisting. I’ve been surprised by the count-down-to-empty coming on at 140 miles into a tank saying I had 30 miles to go and the next gas station 40 miles away. Slowing down increased that 30 miles by over 50%. Normally the count-down-to-empty doesn’t come on until 180-200 miles into a tank.
Anyway, I thought I’d add a little extra storage space for gas by copying something I saw done on http://www.advrider.com/.

The large, 33 oz MSR gas bottles, if filled to the “fill line”, hold 30 oz each. Two of them will give me close to 1/2 gallon of spare fuel. Or a quart of fuel and a quart of oil. The holders are adjustable bicycle water bottle holders. I got adjustable holders because I might want to run different size bottles – say storage for a bottle of wine on the way to the camp site after a food run! These are from Topeak. Bottles and bottle cages purchased from REI. I took the bottles over to the bicycle section to pick the cages that fit best.

I took the right case off the bike and positioned the holders to their approximate location. After deciding where I wanted them I found that the centerline for the holders were perfect when 2” from the edge of the case. The mounting holes were fine at 2 1/4” and 4 3/4” from the bottom. They could have been 1/4” to 1/2” lower, but this is where I wanted them.

I had this stainless steel hardware on hand. The M5x14 is OK, an M5x12 might have been better. The bolts are mounted with the nuts on the outside of the case. I used clear RTV around the bolt heads and inner threads to keep water out of the case. I used blue loctite on the outer threads/nut to keep the hardware from vibrating loose.

5 mm is just over 3/16”. I dimpled the drill points with a center punch then drilled 3/16” holes with a hand drill. I used a reamer and a file to clean up the rough edges both inside and outside of the cases. The brackets easily went on with the above hardware.

After the brackets were mounted I added a little more RTV silicone around the exterior threads using a toothpick to get between the back of the holder and the case. Probably not necessary, but it can’t hurt. I put the case back on the bike, the bottle in the racks, and added a mini-bungi through the holes in the bottle tops to keep them from bouncing out. They’re ready for use this weekend ride to Gardnerville, Nevada.

The thin-as-a-thread bungy was replaced with a strap from REI. Idea shamelessly stolen from this post on Adventure Rider. I like that the strap was available in MSR red!