Topic: My 1971 cb750k1 has slow-moving brown goo in gas tank

[Hondawggie]

Bought a dog-eared 1971 cb750k1 and the gas tank innards had a light brown color -- like a coating or something.

The gas had turned to varnish due to setting so long.  I did my normal approach -- empty the varnish out, then put in a fair amount of lacquer thinner to clear out the old gas remnants, then shake the tank around for a day or so.

Well the brown stuff on the inside of the tank is now runny -- when I tilt the front of the tank upward so the tank is now in a vertical position, the brown goo is slowly flowing downward inside the tank due to gravity.

My questions

1) should I see to it that all the runny tank coating junk is taken out of the tank (yes says my common sense)

2) but how?  Lacquer thinner and 90 degree temps outdoors got it moving like slow lava but its not coming loose enough for me to flush it out.   What solvent or other liquid do I use to remove the tank's brown goo inside?

Note:  the flowing light-brown goo is *not* old gas solids -- if that were the case the flow wouldn't have the same color (light brown) as the tank's inner coating.

[ekpent]

.  You know what you have to do Cowboy---  You got to get her out any means it takes.I have never seen an old sealer flow though,it usually peels.  You have to give us a pic of this stuff. What may have happened is your lac thinner may have partially broke down some old Kreeme,enough to just soften it. Stick the camera in ,close your eyes and shoot-------  PS-Light brown goo may mean rusty mixture---   My method for removing Kreeme and other sealers is furniture strip and that can look pretty messy also,like things from baby butts   --You out there Nick (Tews)   

[Hondawggie]

Good gawd what I wouldn't give to post that pic -- it is flowing slowly, a better view would be a few frames on youtube -- I am not a camera guy though.   I would like to have one of those skinny motion picture cameras they use for operations to put inside the tank's fill hole -- it is real instructive to see what I have long suspected, those tank liners don't last. 

If I don't find some type of more powerful solvent to dissolve this cheap-ass brown goo, I guess filling it up with lacquer thinner and putting it on the hot porch for a few days will help.

I realize pool acid will do it but pool acid in a tank leads to pinholes in the tank.

It needs to be a solvent of some kind.

[ekpent]

As I am in the furniture biz,there is still some very powerful stripper that has not been banned that will make any sealer beg for mercy.The trick is to be able to use it without ruining everything in sight.I have cleaned original paint tanks before of their sealers but it is like a surgeon going in for a procedure 

[Hondawggie]

I'm headed over to Home Depot to buy furniture stripper. 


One thing I AM real good at --  avoiding destruction of an excellent existing paint job when I clean the tank innards.


What is my secret .. I am too got dang cheap to buy a vintage K that still has a good paint job thats how.

Here are pictures of my '71 tank -- notice the top of the tank's paint is all ready for stripping out the tank innards.  Good to go.



I got the flash on my cheap Target camera to show the flowing brown goo, looks like runny dog#$%*e.

[Stev-o]

That is pretty sick looking!

[sandcastcb750]

I'd say you got slimed, but it looks like creamed.

[chewbacca5000]

Cream is soluble in MEK as is redcoat.  You will need MEK to remove this liner.  Good luck!

[Hondawggie]

Okay folks thanks, as we speak I have a fair amount of stripper inside right now and I'm about to drop my chain down inside to hasten the process.  Don't know if the stripper is working yet as I put so much in there you can't see the tank bottom.


If the stripper doesn't work I'm going to try that MEK.

I looked on the Home Depot web site and they have "MEK Substitute" -- that would be like a blow up doll, does not do what you want it to -- I'm in California, does that mean anything about being able to find MEK here?

[Don R]

I wondered about using that adhesive plastic sheeting they sell as temporary carpet protector to protect the paint. I know they sell it at Lowes in the flooring section.

[xsmooth69x]

i should just drop in some ball bearings and shake it to start mixing and breaking everything up

shake shake shake