Appalled - Any ideas?

[Kool_Biker]

Hi all
After only 100 Km of riding my restored Z (oh joy) with my just rebuilt, super clean carbs, I had them removed & dismantled, only to find what seems like huge amounts (of more or less equal portions) of 'residue' in all 6 float bowls.
Yes, there is a brand new filter in line with my unsealed and visually decent fuel tank, and the only additive I used other than regular fuel, was a small amount of Sta-Bil. I should add that the bike worked and sounded good, idled decently etc, but this can't be right. Can it?

P1060519.jpg

Are filters offering so little protection? - I have used a quality but generic Goldwing GL 1000 in line filter.
Is it rust, not sure yet, and does rust flow through a filter?
I have not tried to find out exactly what the residue is yet, and plan on removing the needle valve filters to see what's going on BEFORE them .
As I go along, any ideas appreciated.
Cheers, Aris

[daves79x]

Aris:
Looks to me like fine rust that will indeed go through a filter. Fortunately, it will go through most jets too. But with so short a time for it to be present, you surely need to look further into your tank. The seams and nooks that you can't see visually are where it's hiding. I'd use some rust removing agent (don't know what you have available over there) to be sure you get it all. I like EvapoRust, but molasses has also been chronicled here, as 2 non-toxic ways to get it, and there are several choices of acid that will do the job more quickly.

I wouldn't worry too much about what you can't see in the carbs, as long as it was running OK. Just clean the bowls, new filter, and you'll likely be OK after you get the tank clean.

Dave

[Kool_Biker]

Good stuff Dave, seems reassuring.
I had a look at the tank; There is no rust to be seen (of course there is some, hidden away as you hint).
What I can see, is a very fine coat of a yellow substance, the same colour as the residue I discovered in the bowls . Stale fuel residue, remains of an old fuel additive? Who knows.
What ever, I am planning to do some serious flushing (any ideas?) and then use a good rust removing agent in the end, see what we get.
Thanks for the quick response!
Aris

[daves79x]

Aris:
Then you do indeed need to thoroughly wash out the tank of the dried fuel residue - THAT will clog up the carbs as it dissolves and comes through (though your filter should catch that). I use Marine Clean, a strong detergent made specifically for removing varnish and fuel residue from fuel tanks, and lots of other uses too. You can get it from a company here called POR-15, but I don't know about international shipping. A gallon is pretty heavy.

You could use any very strong detergent available first, then see how the tank looks. You do need to clear all the varnish and yellowing out before de-rusting. Use lots and lots of hot water to rinse, then turn the tank upside-down after draining to pool the remaining water around the fuel cap. Hot water in the hot sun will evaporate quickly and you can pat the water out from around the fuel opening with paper towels. Then de-rust however you choose. Good luck.

Dave

[Kool_Biker]

Dave, thanks for the guidance.
I have now formulated a plan to clean the entire supply system, from the tank, including feed pipes and filter, all the way to my cleaned-again carbs.
Luckily enough EvapoRust is freely available over here and I have got myself 2 gallons (to preventively do my GL 1000 Goldwing as well) of the stuff.
To dislodge and clear the old fuel residue inside the tank I will probably have to use a paint thinner, I can't locate anything more environmentally friendly over here to do the job adequately ...
I am attaching a pic which might show the dull yellow residue inside my tank, the only part of the bike I did not really zero in during restoration, believing that line filters have magic properties. Evidently, they dont!

P1060545.jpg

But the dull yellow residue was not confined in the bowls as evidenced in the pic below, so more cleaning work before closing the carbs again ...

P1060535.jpg

Let's hope all goes well.
Regards
Aris

[Don]

Aris

Naval Jelly will do a great job of removing whatever rust is trapped in the seams of your tank

Dissolve 1/2 bottle of it in a couple liters of very warm water, fill your tank halfway with very warm water, pour in your dissolved jelly and then fill the tank to the brim with very warm water and let it sit 24 hours. The 'warmer' the water the better . . . . I heated some on the stove - Not to boiling, but very, very warm

Dump it out and rinse the tank several times with very warm water and then use whatever soap solution you have and rinse it seveal more times - I used the Marine Clean that Dave recommended

I used this method to clean a *very* rusty tank on my KLR - I got at least a cupful of solid rust (looked like coffee grounds) out of the tank and what remained after this process was very clean metal. The naval jelly eats away the rust but doesn't harm the metal

Don

[Kool_Biker]

Don hi, I am a bit confused.
My tank has VERY light rust, if any, and I thought that EvapoRust as already recommended by Dave should take care of this.
BEFORE using this, I am planning to use a solvent (paint thinner) to remove any traces of stale fuel residue, thus also preparing the tank for EvapoRust to act.
Am I missing anything? Especially as I do not have access to many branded products around here, e.g. Naval Jelly, and have managed (amazing!) to find and purchase EvapoRust?
Cheers, Aris

[daves79x]

Aris:
I think Don is just saying that he rinsed the tank after the de-rusting process with Marine Clean and then clean water. Not sure if he had a build up of varnish as you do, or just a lot of rust. The way you probably want to proceed is to get the most varnish/fuel deposits out of the tank first with something that will dissolve it. Marine clean works for that specifically, but you can use whatever strong solvent you have available.

The Evapo Rust will work just fine to remove what rust is left and will work pretty quickly on the mild rust you seem to have. Down side there is that you will need to rotate the tank to various positions and let it set for the 2 gallons you have to get the whole tank. Likely the lower seams are the worst and 2 gallons will get that with the tank just sitting upright. Get yourself one of the adjustable plumbing plugs (plastic plug with a rubber disc around that expands as you tighten the wing nut) to fit the tank opening. Cut a couple of small pieces of inner tube and fold them into the notches for the tabs of the normal cap. Then put the adjustable plug in the opening and tighten. It will seal completely when you turn the tank upside down.

Your fresh gas in the tank seems to be slowly dissolving the varnish and re-depositing it in your carbs, along with some rust. The above process should take care of all that.

30 years of time has not been generally kind to our CBXs unless meticulous care has been taken of them.

Dave

[Kool_Biker]

I have used all sorts of solvents I can source locally, without reverting to too aggressive stuff such as hydrochloric acid, and have utterly failed to get rid of the 'dull yellow' residue you might remember from the beginning of this thread .

P1060707.jpg

It will sort of come out if I scratch it with a piece of cloth at the end of a screw driver, but will not move in any other way and as you know access is limited ...

P1060670.jpg

There might me chemicals where you live guys, Marine Clean sounds good, that will do the job, but I cannot source them over here.

So what I am thinking of is reconnect my tank, use my bike, but for the next few tankfulls of petrol, mix some 'STP Petrol Treatment' hope you all know it, which will hopefully eventually dissolve and get rid of this residue through my exhaust pipes.

Your thoughts?
Cheers, Aris

[daves79x]

Aris:
Try boiling hot soapy water - it looks to be a waxy substance that might melt off in very hot water.

Dave

[Kool_Biker]

I have used hot water with my detergent, about 50'C, with no success ...
You believe I should go higher, circa 90'C ~ 95'C?
Perhaps I could try locally near the neck, with my trusted heat gun, see what happens ..
Thanks, Aris

[Goss]

Try some Acetone on a rag with your screwdriver isf it comes really easily then pour a pint in and swill around. I would remove the fuel tap and filter before though.

Regards

Goss

[Kool_Biker]

Dave, Goss
At last, all the residue is now gone.

Hot water did get rid of some of the dull yellow residue, but not much. Sticky bugger.
It was 2 litres of pure acetone, agitated rigorously for ~10 minutes, which did the trick.
It was very satisfying to see the colourless fluid come out the other end a good yellow colour, leaving the inside of the tank almost spotless.

That's it, the tank is going back on the bike in the morning and then we have the ... proof of the pudding.

Thanks everyone, I never seize to be amazed by the sheer knowhow AND willingness to help in this great forum.

P.S. Great Moto Martin youtube video, Goss!

[Don]

Aris,

Could it be that what you were dealing with was some sort of 'treatment' a previous owner put in the tank to solve his rust problem??

Glad you got it all out - I would think about sealing it with something now though . . . . that pretty, clean metal might begin to rust. Maybe you have 'real' gas in Greece though, as opposed to this water-laced alcohol stuff we have to deal with over here

Don

[Kool_Biker]

Don
I am inclined to believe the best protection for now, is keeping my tank full at all times, specially during the winter and when the bike is laid up.
Not sure what the exact composition of fuel is over here (I don't think anybody knows!) and frankly, living a dry-ish country and pampering of our bikes in a way never envisioned by Honda back in the seventies, should do it.
I will keep a close eye on the situation of course.
Can you suggest a good in line fuel filter I could source, may be from Amazon?
Thanks, Aris