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Sullivan Flex tank issue

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Old 12-09-2017, 05:03 AM
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Trax540
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Default Sullivan Flex tank issue

Hey all,
Im setting up an 8oz Sullivan flex tank and im having an issue with the clunk im hoping someone has an idea why.
Ive setup quite afew before but never ran into this.

When i run my tube through the stopper and attach my clunk line. Ive got it set to about 1/16 before back of tank when tank is upright, so I know its not binding on tank wall. However, This clunk doesnt seem to want to slide around the tank no matter what position i go. Definitly when i flip inverted it only flexes midway of tank never touching what would technically be considered top of tank.
Being flex tank I understand the composition seems softer than a hard solid tank. But Again it has trouble moving into even the corners of the tank.

Its brand new silicon tubing but seems it doesnt want to flex, Obviously i cant adjust the length or else it will bind on walls, or be to short.

Any help is appreciated.
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Old 12-09-2017, 05:50 AM
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Sounds like you may have thick wall silicon tube. There is a thin wall tube that works well as a clunk line.

Alternatively you could try a heavier clunk but I would go for the thin wall tube.
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Old 12-09-2017, 06:10 AM
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Trax540
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Any idea where i can get thin wall?
Only thing I see on Tower is Standard Silicon tubing. Thats currently what im using.

Possibly anyone have a link to some thin wall tube

Thanks!
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Old 12-09-2017, 08:29 AM
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Just add some weight to your clunk or buy a heavier one. Thick copper wire like Romex works, or I even once pounded a piece of lead flat and wrapped it around.
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Old 12-09-2017, 11:55 AM
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Originally Posted by Trax540 View Post
Any idea where i can get thin wall?
Only thing I see on Tower is Standard Silicon tubing. Thats currently what im using.

Possibly anyone have a link to some thin wall tube

Thanks!
https://www.ebay.ca/itm/1M-Food-Grad...7QgbhOuD8ro49Q
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Old 12-09-2017, 01:07 PM
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Have you tried Sullivan's latest:

Sullivan ProFlex?

Check out Tower.....
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Old 12-10-2017, 02:02 PM
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Trax540
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I did see that new Sullivan tubing, Man 4$ a ft is pricey. I know they named it Proflex but is it really much better? From what i gather its more so great because you can use it for all fuel types instead of restricted to gas/diesel or Nitro

Ive ordered up some 3mm ID thin wall tubing and I will see how that flexes around in the tank
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Old 12-11-2017, 06:15 AM
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Two other work arounds to this problem. First the larger the tank the longer the internal flex line and therefore the more flexable it becomes. So moveing perhaps from an eight ounce to a ten ounce just may take care of the problem.

If that is not desirable or possible then give consideration to how you have assembled the bung plug. How much of the solid through tube do you have protruding past the backside of the bung plug. An excessive protrusion here will rob flexability of the internal pickup line. I like to keep these protrusions quite short on the smaller tanks for this reason.

The other extreme of this consideration is with very large tanks the fellows will sometimes add solid sections of tube to the internal pickup line reducing flexabiity to prevent the pickup tube from flopping forward and cutting off fuel during a firm arrival.

John
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Old 12-11-2017, 12:47 PM
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Cant move up to a 10oz.
The tank compartment just isnt big enough for it. And after inspecting these 2 tanks i have, I'm noticing that the inside is extremely soft. Almost Gel like coating on the inside of the tank. I think that is contributing to 1 of my issues which is the clunk just freely sliding back and forth.
Doesnt however solve the flex issue.
I ran the tube up as close to the stopper as i could just to see, and the tube still wont flop to top of tank area when inverted.

Just waiting on that thin wall tubing to arrive and i will try that to see if it helps
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Old 12-11-2017, 07:08 PM
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Pro Flex tubing is very flimsy, but also durable. Sullivan claims it's more durable than silicone, which may be true. It's so flexible, in fact, that you always need a stiff section of tubing in the middle to make sure you don't get your clunk stuck in the front of the tank.
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Old 12-12-2017, 03:52 AM
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Originally Posted by JohnBuckner View Post
Two other work arounds to this problem. First the larger the tank the longer the internal flex line and therefore the more flexable it becomes. So moveing perhaps from an eight ounce to a ten ounce just may take care of the problem.

If that is not desirable or possible then give consideration to how you have assembled the bung plug. How much of the solid through tube do you have protruding past the backside of the bung plug. An excessive protrusion here will rob flexability of the internal pickup line. I like to keep these protrusions quite short on the smaller tanks for this reason.

John
From what I can decipher from the OP's posts, I think that you have the answer.
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Old 12-28-2017, 10:06 PM
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I tend to use what I have on hand to fix a problem. My immediate impulse to this problem would be to use a lead bullet as a weight on the clunk line to make the line flex enough. A .38 caliber bullet drilled from tip to tail the same size as the OD of the line would allow the bullet to slide on the line ahead of the clunk, then put the clunk on, If that is too much weight, trim the bullet length-wise until the desired weight is attained. After trimming the bullet to the correct weight, a drop of some sort of fuel proof glue should hold the bullet in place. Cheap, easy fix. I think. Worth a try.
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Old 12-28-2017, 10:20 PM
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Or in fishing, a lead bullet weight used ahead of a plastic worm. The hole would have to be enlarged a bit, but it is already there, Just make it fit snugly around the fuel line.
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