GT750 Tank Issues

[DesertKZ]

Scored a '75 GT750 this weekend for a "smokin" deal. You could tell the guy that owned it put the bare amount of $ possibly intending to just flip it. Anyways, the inside of the gas tank was POR-15'd recently and looks decent. However, there are some pinholes that seep gas near the bottom of the tank and I have a few questions.

1. Can I weld up those pinholes even though there's POR15 on the other side?
2. Absolute BEST method for removing all fumes, don't know if the POR15 soaked up the fuel.

I have been checking eBay and the GT750 tanks on there look worse than mine, plus mine doesn't have any dents so that's a plus.

 

[DesertKZ]

I think, after reading the on the absolutely true interweb, I have come up with a plan for now while I try to source another tank.

Since there are only 3 or 4 pinholes, I am going to slightly "dent" them inward with a small nail and use the putty that's supposedly fuel proof, specifically made for gas tanks, or maybe try to solder them with an iron vice a torch. I'll try and recoat it again, and if worst case, only out $25. I hate to do this so half-assed but I want to get a little riding in before I tear it down this winter.

Others have said fiberglass? I think the gas would wear it down over time.

I'm so skeptical from ordering one off eBay and that'll be in the same boat eventually.

 

[xb33bsa]

nothing wrong with solder use plumbers flux paste and solid solder not rosin core

 

[DesertKZ]

nothing wrong with solder use plumbers flux paste and solid solder not rosin core

The pin holes are so small though, you think the solder will seep in there?

 

[Maritime]

The pin holes are so small though, you think the solder will seep in there?

Flux should pull it in and if you apply the heat behind or below the hole it should make the solder flow towards the heat.

 

[xb33bsa]

you will be buiding a layer of lead to cover the hole
you could evan laminate a thin copper sheet piece over the hole
use a soldering copper not a torch flame

 

[DesertKZ]

I filled the tank up with soapy H2O all the way to the top, found a rubber diaphram that covered the filler, poked a hole in it and put some serious compressed air into there. So much the tank bulged a little.... I figure that would be the sure test of its rigidity. In all, only two small, less than a mm pinholes about two inches apart. I'm thinking I try and solder these and see what happens.....

 

[xb33bsa]

good luck
for future reference your testing method is wrong all wrong and couldeasily damage the tank
never put compressed air in a tank
do not test for leaks with water, you may not find all of them, water is too thick
test for leaks with air and soapy water to find the bubbles
to charge the tank with air just close the cap and blow with your own air from your lungs into a hose attached to the petcock that is all the pressure you need

 

[DesertKZ]

good luck
for future reference your testing method is wrong all wrong and couldeasily damage the tank
never put compressed air in a tank
do not test for leaks with water, you may not find all of them, water is too thick
test for leaks with air and soapy water to find the bubbles
to charge the tank with air just close the cap and blow with your own air from your lungs into a hose attached to the petcock that is all the pressure you need

Appreciate the heads up, thanks. The tank may be too far gone which is why I decided to push alot of air through it, I used soapy water (see post above) I'll keep what you said in mind next time.

 

[teazer]

Kawasaki GT750 or Suzuki? I have tanks for Suzuki GT750 in Red or gray in pretty reasonable condition but nothing from KHI.

 

[DesertKZ]

Kawasaki GT750 or Suzuki? I have tanks for Suzuki GT750 in Red or gray in pretty reasonable condition but nothing from KHI.

I've read your posts and admire your builds, I'll be in touch if I can't sort this out. Thanks. Suzuki GT750

 

[teazer]

You can do this:

as long as you can dig out any old liner material.

My last tank was semi porous so I repaired that with bronze rod and then sealed it with Caswell tank liner. For the filler neck you need a smashed i.e. cheap GSXR/Bandit/Katana tank k to cut out the filler cap section. The tricky part is awlays the fuel/water drain through teh bottom, but it's not complicated - just fiddly.

or try a GS1100 tank for something different and integrate it into the seat and new side covers.

In that pic you can see lots of blue tape top mock up general shape. It's cheap and quick to mock up shapes and see what works. Or you can trim teh nbottom edge for the classic table top (flat bottom) look

There are all sorts of options open to you.

 

[bradj]

I also have a blue kettle tank if something falls throu with teazers
in fact i could live with out the entire bike i got enough projects at the moment

 

[teazer]

74 L model in blue. Nice.

 

[bradj]

74 L model in blue. Nice.

i guess, does the L stand for hard to push

 

[xb33bsa]

i guess, does the L stand for hard to push

hahaha yes when pronounced like an R,get it ??

 

[DesertKZ]

Ugh, after many rinsings with acetone, thinner, every large bolt/nut I could find, the inside looked pretty good. I soldered up a few pinholes and they're holding up. Aircraft remover on the whole tank, no bondo. The one dent it had I pulled out with a HF stud welder. I chose to use the POR-15 tank liner and it came out awesome. I'm not going to put any fancy paint on it for awhile to see how she holds up. Appreciate all the input.

 

[bradj]

hahaha yes when pronounced like an R,get it ??

this just sunk in haha pleasure as always xb33junk