here pretty soon going to be painting my Sporty and would really like to put in a new Fuel Filler Bung to get a screw in style cap. who ever had the bike before me put on an aftermarket sport bob style tank and i like the looks of it but it has a 1/4 turn style cap and i really dont care for it at all and i saw that J&P Cycles has a weld in bung you can get for the screw in caps but was wondering if anyone had ever done it before and how did it work out. i know its pretty sketchy welding on a gas tank and if i do have it done ill let the tank sit for a while to get all the fumes out but was courious if any of you that have done it have any tips for that as well. any ideas will help

 

I'd call a welder, or custom bike builder for guidance. I don't think sitting/time will make it safe - believe there are other safety measures for welding in hazardous conditions.

 

I've heard it done two ways. One is to remove, and wash it out 10 or 12 times. Fill with hot water, dump, fill, dump, etc, etc. Put your nose up to it, still smells strongly of gasoline repeat. Let it sit for a bit after your satisfied and go.

Another way I've heard about will only work if you've got access to some dry ice. Frozen Carbon dioxide. Put some pieces in the tank, wait a few minutes and the releasing dioxide should displace any oxygen that the fuel vapor would need to ignite.

Take my advice for how much you paid for it though. Never welded a tank myself before, mainly just vehicle frames lol. I'd probably bite the bullet and call someone knowledgeable if it were me

 

first you got to get the old one out with what ever means,neatly,leaving correct size hole for new bung(better the fit up the better the weld job will be) fit the new one in and have some one that tig welds meld it in for you.Tig welder with foot control to control the heat would do the best and then comes the blending in process so after it is painted it will look like it come that way.Good luck

 

I've seen it done filled with water,but you need a pro to do this.

 

We have a welding shop here in town think ill just have them Tig it for me and be done with it.

 

I weld up broken tanks all the time I just fill them with water with a bit of soap in it , leave about 1" air space around the work area . Helps keep the tank from warping to much and much easier to find pin holes you may have missed in the weld . Tig is the only way to go if you have one available , mig or stick is going to take some finishing make pretty again and you better have a good hand at welding with those .

 

At the factory in Kansas City they braze them, I think.

 

I just repositioned my cross-over fittings on my 2006 softail gas tank so that I could install quick-disconnect coupling. Those fittings are brazed in. Make sure you vent the tank after draining it, take everything off and out, that way there are plenty of openings (large ones) rinse several times with water/soap, vent some more. By leaving everything open and off like the fuel pump panel off, if there is a flash from some residue the tank can't explode because it can't build up pressure. Just have fire extinguisher handy and nothing flammable around. Should be fine.

 

This is spot on. Another thing is when you think you've got it clean enough(no gas) Clean it a couple more times just for ****'s and giggles.
It's probably going to warp some know matter how you slice it though.If you don't weld pretty well,practice first,a lot. For **** like this I like to use a pulse setting on the tig welder to really focus the heat right where you want it.Biggest mistake I've seen is guys not using enough heat and sitting on a part for too long because they can't control the puddle with the heat where it should be. That will spread the heat way out and overheat everything and cause a **** ton of warpage.