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Old 02-03-2009, 08:49 PM
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Retmachinist Retmachinist is offline
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Join Date: Oct 2008
Location: Urbandale Ia
Posts: 637
Default Re: gas tank filler pipe and cap

Originally Posted by redpiper777 View Post
This is what I did.....This is just copied from a reply I gave about building a custom tank at motoredbikes...

"Hey there, I made a rather simple one for my "board tracker" style bike...A bit on the pricey side though...I ordered 18" of 3" diam brass tubing and two domed end caps...This can be done with thin walled steel tubing ( I'll go with steel next time ) at a much lower price I'm sure but you may have to order the end caps in brass or stainless to get smooth caps..Anyway, I ordered from a company that sells tubing for bar rails and hand rails and stuff like that...I started by cutting out the filler neck and cap from the stock supplied tank...I soldered that in and found that the neck was too short and the cap was hitting my bike frame...I went to a plumbing store and got a chrome drain pipe and cut that to about 4 inches ( to clear my upper frame tube ) and soldered that to the filler neck and did a J.B. Weld job around the neck and some sanding to make it a smooth transition into the tank...I will have to paint my tank because I put a few deep scratches in the brass building it...Then I went to the local "Carquest" auto parts store and bought a better fuel petcock for like 6 bucks made by "Prime Line" and a brass female fitting which was soldered into the bottom of the tank and then threaded in the petcock...Oh and by the way, because of the flair on the filler neck I had find another type of gas cap so I purchased a 1 1/2" test plug that expands a rubber plug when the wing nut on the top is cranked down..I have since modified the test plug to look a little nicer on the filler neck..Anyway thats how I did it and and it held pressure on the test and doesnt leak..I'm guessing it holds about 1 and 1/2 the amount of fuel the other tank held but to be honest I havent measured it yet...Heres a couple of older pics, I took tons while making the tank but I dont have any new ones yet... I'll try to upload some new ones soon...To answer another of your questions, I think I have about $70 into this tank but it can be done cheaper...I just recently ground the edge of that test plug metal cap and J.B. welded it into the plumbing pipe threaded cap ring but I dont have a pic yet...Makes it look like a real gas cap....Good luck with whatever you decide to do."

By the way that test plug was only 2.50 so buy a few...I'm going to carry an extra in my tool pouch on the bike...I'm not absolutely positive that the gas wont eat the rubber plug in time so I got a spare...I have talked to a few people and they said it should be fine for many years actually...

and heres a couple pics..
How is your tank vented. You will have to have a vented cap.

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