Auxiliary fuel tanks
Recently I have been having a local fabricator working on a long range auxiliary tank for my Xchallenge. I picked it up last night and put 9.7 L in it, but I reckon I could squeeze 10L in there. I did the daily commute with the tank on today and it is working well. Fuel is being used from the rear tank and handling of the bike is virtually unaffected. I am aware that the suspension is compressing a fraction more than normal so I will put some extra air in the shock tomorrow.
The tank is mounted firmly on the bike with no movement. I am going to get a friend to follow me soon to look for signs of flexing but I don't expect there to be any. I did have the lower bolt on the subframe diagonal come out somewhere on the journey, but as I didn't tighten them up fully last night that will be my fault. Even so there is still no movement on the tank. We replaced the bolts when we fitted the tank as the originals got a bit chewed up. They had practically seized in there and I am going to copper-slip the new ones, but I didn't want to tighten them fully in case they got stuck again.
The pics show the tank clearly. The welding is really neat and the tank fitted perfectly. Clive said he used magnesium wire to weld rather than silicon. Apparently silicon wire is much easier to weld with but goes white if you try to anodise it. The middle bit of the tank is 3mm alloy, 16 guage I think Clive said, and the sides are 14 guage which is slightly thinner. There are 2 brackets on the top and one long one down the front edge.
I haven't let the shock down yet but will do that over the weekend. However if you look from the rear there is lateral clearance between the chain and the tank. On the wooden blank the chainguard touched the tank with no air in the shock but the chain would not. I believe the final tank is the same but will confirm that.
On the final versions I think Clive wants to radius the backets to make it a bit neater. The fuel outlet will be moved up and in so it is behind the plastics and the optional scottoiler attachment boss may also be repositioned further in.
Clive will sell this tank for the GX bikes, black anodised, for £325. I have also spoken to a dealer who is so impressed with the GX tank that he is prepared to let Clive have access to an F800GS. I expect that Clive may want a deposit or some kind of assurance that he will definitely sell some of these as there is a fair bit of money and time in making the first tank. He is happy to make a variety of parts for any bike providing he can access to a bike to work from. If you guys are interested let me know and I will get you Clives contact details.
I think I might need a repalcement seat though, as I'm not sure I could manage the 300 mile tank range without getting piles.