BMW 650X Aux Gas Tank, Build one yourself

I really love my 650 X challenge, but the limited fuel range has been a problem. Many places we like to ride, don't have fuel available and I need more range. Didn't really like the look of the very oversized Touratech monster tank nor did I like the high price tag that went with it. I have been looking at a 1.5 gallon tank made by Kolpin. You can get them several places. I got mine at Rocky Mt.

http://www.rockymountainmc.com/productDetail.do?navType=type&navTitle=ATV+Accessories&webTypeId=170&webCatId=24&vehicleType=&pageLinkUri=&prodFamilyId=11787

My luggage rack has an aluminum top plate held in place with three bolts/screws. I had figured I would just remove the top plate and adapt the tank mounting rack so it could be secured to the luggage rack using the same three screws. However, I found the screws were very small (M5) and the mounting tabs were very weak looking. So I had to remove the rack and add some additional (and stronger) mounting tabs.




Once the paint was dry and I reinstalled the luggage rack, I could start fabricating the tank mount. It was a fairly straight forward project. Here is the tank mount:





Notice the cut out area so I can get the key in to remove the seat with the tank rack in place.

With the tank in place:










The tank rack can be quickly removed and the stock top plate installed when I don't need the extra fuel range.

I also wanted a way to mount a tail bag for those multi day trips. I made a aluminum plate that can mount on top of the luggage rack with either the tank rack in place or removed. The plate mounts using the same three mounting screws as the original top plate.







The tank claims to hold 1.5 gallons. I went to the gas station and put 1.5 gallons in the tank and still had a little room left. You may of noticed that I choose to go with the white (water) tank as opposed to the red (gas) tank. I looked closely at both tanks and they appear to be the same except for the color. I figured I would like the look of a white tank rather than a red tank. The red gas tank will fit the same rack.

I figure my range is now well over 200 miles. That is the same of my wife's LC4 with the 5 gallon tank on it. Next weekend, we plan of taking a long ride in SE Oregon where gas stations are few and far between. We will get a chance to put the new tank to the test.

This was a fairly easy project that almost anyone with normal shop tools including a welder, cutting torch and grinder could do. Total cost for the tank, mount, aluminum, iron and bolts came to just under $100.

Good solution!

Sweet, thanks for posting.

Does the weight off to the side throw you off much?

Good job ! Thanks for the info.

Way to go!!

Sarah

Good low tech solution. Let us know if this setup holds up to a real pounding or even if it fails. It's a tidy, safe mount that should work on a numberof bikes.

Thanks for sharing your skillls, DD

Very sanitiary solution. What is that aluminum material? If it came from the hardware store don't expect it to survive even a simple fall. If you got some good _tempered_ aluminum plate from the steel supply, you are perhaps good to go.

You will have to fill the tank and field test it by falling at 15 mph on the right side, then get back to us.

hmm looks like a new design, the standard Kolpin fuel pack jr is 1.25gallons and 3" thick, looks like yours is an extra 1\4 gallon (or more like you said) but 4.5" thick. I'll probably go with the two thinner ones because it looks like I can squeeze them in between the bike and pannier, for those of you with caribou cases you should also be able to do the same just like caribou offers the tool box option mounted to the inside of their boxes.

Did not notice it back there at all while riding. This included every thing from pavement to gravel roads to dirt roads to very off road (little jumps, ruts, etc) to snow and ice covered roads. (the tank didn't bother me any, but the ice did) The only time I noticed the tank was I brushed my foot on it getting off and on. Need to swing the leg a little higher.

Tested the new tank setup yesterday in SE Oregon. Left Burns with full tanks. At approximately 100 miles, dumped the gas from the aux tank into the main tank. The low fuel light came on at 198 miles. If I wouldn't of had the long uphill section of snow and ice covered road on the Steens loop road where I spun my rear tire for long periods without gaining any distance, I should of made an honest 200 miles for sure before the low fuel light. The actual tank stayed put without any issues.

The only complaint with the setup is with the design of the tank cap and spout. It is like all new gas cans. The spout and cap suck. They are difficult to get on and off and use without getting gas on your hands.

Still, all in all, the setup did what I wanted. Provide a low cost, useable solution to get my range up to 200 + miles.

I did a similar setup..... I just bolted the kolpin holder underneath the rack though. I've had several crashes so far with it and nothing got bent.

Just be careful when using it.... There was only 1 time that I NEEDED it and I'll be damned if I didn't drop it and spill half of it.

Thanks for the info. I am currently in the process of making my own luggage rack for my xcountry and was thinking about possible ways to mount extra fuel to it. Well, looks like this will work for what i'm going to be doing. I currently get about 130 miles to the tank before fill up is required so adding this extra 1.5 will give me at least another 80 or so to not worry about stopping for fuel. I ordered the bracket and will start to work on this as soon as I get it. Will post pics once it's done.

You can pay for a two or three week vacation with the money you saved from that solution compared to the Touratech.

Wow, that looks great! I want to do something like that for mine...sadly I lack the skills/tools. :huh But the shop guy at work is a bike nut and would probably help me.

Do you think some triangular gussets where the 90 degree bend is from the rack to the fuel tank mount would help prevent flex and possible metal fatigue down the road? I guess the lower strap would take care of it though.

The bracket for the tank is plenty strong. You can pick the bike up with it. It wouldn't hurt to brace it but you don't have too.

Now I gotta figger out a way to do this to my BRP

.......put down the welding gear and back away slowly.......... Bruce

Your all insane!!!
Wait I am here too.

Is it still holding up pretty good? Any problems?

Still holding up fine. Used it last weekend. With the better weather approaching, will get a chance to test it some more.

Ask again this fall, by then it will have been used on several trips.