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Discussion Starter · #1 ·
Hello, I have a '73 CB350 where the rear gas tank connection ports are blocked. The tank was resealed at some point in it's life and I suspect this is the culprit. I can run a pipe cleaner (smoking pipe type) through one side and it will go pretty much up to where the pipe comes out of the tank. On the other side the pipe cleaner goes in maybe 1/2" and hits blockage. Has anyone ever dealt with this dilemma? I discovered this after removing the tank to do some carb work.
 

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Discussion Starter · #2 · (Edited)
I just found an old thread dealing with this issue, a section of it is below, it was from 2012. So the little torch will help to melt the sealer. I really hate using a flame around a gas tank! I may try it using a heat gun rather than a flame.
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I couldn't get my hands on that tool but I ended up clearing it out using a turbo torch and piece of safety wire. There is a burn mark on the bottom of the tank, but it beats the hell out of cutting and welding or having to replace the whole tank.
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Discussion Starter · #3 ·
I made progress on the tank. I drained the fuel, it was quite nasty since the left side had never drained to the petcock. I perched the tank on my work stand and dribbled Acetone into one of the drain tubes. The inside of the gas cap has the tank sealer on it so I dabbed some Acetone on it to see if it softened it and it did. I used a small twisted-wire cable to snake down the tube until it hit that obstruction then proceeded to twist and push and viola! it broke through. Cool! The right side is a different story. It is blocked way worse than the left was. On the left I could run a wire all the way to where the tube hit the tank and that is where the blockage was. On the right side the blockage is only 1/2" in from the end of the tube. I put a small drill bit in a tap holder and tried to 'drill' out the blockage. That did not do much until I heated that tube with a heat gun. Not sure what I was getting out of there, it was brown. The tank sealer is white. Anyway, progress is being made, I am halfway down the tube, Acetone is sitting working as we speak. I will continue along these lines, I am hoping it is successful. What can go wrong?
 

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Discussion Starter · #4 ·
Success! I kept prodding with twisted-wire cable and that did not do much so I tried a small steel wire, fence wire maybe it is called, and was able to bend it close to the profile of the bend and shove it in twisting and turning and I could feel progress. I could also see brown gunk coming up in the tube that was now filled with Acetone. After a bit more prodding and pushing I was able to get my twisted-wire cable to pop through. Yippee! I hooked the two ports together with a hose, dumped a quart of gas in and tilted the tank to fill the bottom of both halves, pulled the hose of on side and magically I have gas flowing from both side just like it was supposed to, awesome! It's the little things in life that keep us going!

I hope this helps anyone else who has this problem. I did not even know it was a problem until I removed the tank and found a broken hose connecting the two side and thought 'Why is this not leaking?'.
 

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Discussion Starter · #6 ·
You all may find this funny.... When I removed the tank I did not have to disconnect the 'equalizer hose', because it was broken and the tank just pulled right up on the ass end! I just learned that it is supposed to be connected under the top frame tube and must be disconnected in order to remove the tank. This became obvious when I connected the equalizer hose with the tank off the bike then set the tank on the frame and went WTF?? Ah, learning experience, life is like that.
 

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A good way to clear those crossover tubes if they get plugged is to cut a short piece of stranded wire cable, like a piece of throttle cable, for example. Chuck one end into your electric drill, and run it at slow speed inside the tube. The cable will snake around the bend like a rotor rooter.

The problem with acetone is that it has a 0°F flash point, turning your tank into a pretty good bomb. Also, it sounds like a previous owner lined the inside of the tank. White color sounds suspiciously like Kreme, which IMHO is the worst liner you can buy. The acetone will likely dissolve it and make it start to delaminate inside the tank. If that happens the tank will need to have the liner stripped out and be redone. I would use plain old vinegar for that. It will eat the Kreme liner. I would not recommend Acetone, though I am sure others would. Here is a Kreme liner that I once removed with vinegar. Most of it came out in one big chunk.

Anyway, all's well that ends well, and you got 'er done -- at least for now.
 
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Discussion Starter · #8 ·
Thanks for the advice. The Acetone was dripped into the crossover tubes from the outside, very little would have gotten into the tank plus the tank was refilled with gas shortly after I unplugged the two tubes so I am not worried about it's effect on the liner.
 
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