Varnish in fuel tank

[texasplumr]

I picked up an 87 Hurricane cheap this week. It hasn't run in four years. I cleaned out the carbs and got it running using a remote fuel cell. Looking inside the tank I can see alot of varnish build up and was wondering what those of you who have done restores use to clean that out?

I've heard of acetone and hex nuts before but since I haven't ever had to do this, I was wondering what all of my options are.

I know it isn't a Blackbird but also know alot of you used to own these and some probably still do. Besides, I've gotten better tech tips from this forum than any on the internet!

Thanks!

Russ

[Redbird]

Don't use nuts, you'll be picking them out of there with a magnet forever. Use a length of chain. That's usually for rust, anyway.

[txstrtxx]

I picked up an 87 Hurricane cheap this week. It hasn't run in four years. I cleaned out the carbs and got it running using a remote fuel cell. Looking inside the tank I can see alot of varnish build up and was wondering what those of you who have done restores use to clean that out?

I've heard of acetone and hex nuts before but since I haven't ever had to do this, I was wondering what all of my options are.

I know it isn't a Blackbird but also know alot of you used to own these and some probably still do. Besides, I've gotten better tech tips from this forum than any on the internet!

Thanks!

Russ

take it to a carwash and spray it out with a hipressor hose ,then take it to a radiator shop have it boiled out and re lined

[mikesail]

Here is my 2 cents.....

If there is only varnish, and no rust, don't mess with it. The varnish will slowly dissolve in the fresh gas and be consumed with no problems.

If you scrape it out by any mechanical method, you will have flakes of it getting into the filter or carb and possibly clogging or causing fuel flow issues.

when a fuel system gets varnished heavily, it is really only a problem for small passages and valves, also the tank sender if you have one.

[Zero Knievel]

I thought they sold a 2-stage chem kit to clean out any gum and varnish and then re-line the tank (if needed) for around $60-70.

I know a guy who had to restore a really bad HD gas tank (came from a vintage model...no replacement to be had). He just keep filling it with vinegar and letting it percolate with a low pressure air hose up the petcock. After a few days of that dissolving rust and gum, he relined the tank and prepped it for priming and painting.

[rockmeupto125]

One of the bikes I salvaged had been sitting for a couple of years. When I opened the tank, there was a sticky coating in the lower half of the tank. Removing the fuel pump and sending unit, I could see inside enough to know that the coating was nearly half an inch thick in places. It was near solid, and could not be removed. the pump and sending unit were ruined. Not knowing what I could do with it I left the bare tank hung on the wall without fuel pump or filler door in place. 6 months later, that layer of tar was virtually nonexistant...just a discoloration. I tried to dig at the edge of the discoloration, brushed with kerosene, and nothing changed. Perhaps in time the layer of varnish would dissolve with continued immersion in gasoline, but I wouldn't worry about it.

Mechanical means such as gravel, nuts, or chains are helpful to flay rust off the sheet metal, but I can't see them being very effective against this type of film. And I'd much rather have a tank with some light rust in it than a tank that's been kreemed.

[cbrxxquad]

I was thinking paint remover, or carb cleaner, I know some carb vat caustic will too. It is just the paint on the outside that will be hard to save.

[RXX]

One of the bikes I salvaged had been sitting for a couple of years. When I opened the tank, there was a sticky coating in the lower half of the tank. Removing the fuel pump and sending unit, I could see inside enough to know that the coating was nearly half an inch thick in places. It was near solid, and could not be removed. the pump and sending unit were ruined. Not knowing what I could do with it I left the bare tank hung on the wall without fuel pump or filler door in place. 6 months later, that layer of tar was virtually nonexistant...just a discoloration. I tried to dig at the edge of the discoloration, brushed with kerosene, and nothing changed. Perhaps in time the layer of varnish would dissolve with continued immersion in gasoline, but I wouldn't worry about it.

Mechanical means such as gravel, nuts, or chains are helpful to flay rust off the sheet metal, but I can't see them being very effective against this type of film. And I'd much rather have a tank with some light rust in it than a tank that's been kreemed.

Why is that, Joe? I have a couple old bikes waiting for me to wrench, and I just assumed I would kreem them. I did it once to a sportster and didn't have any issues, but I only put about 30K on it before I sold it to some beaner in El Paso.

Please enlighten me/us?

[rockmeupto125]

Why is that, Joe? I have a couple old bikes waiting for me to wrench, and I just assumed I would kreem them. I did it once to a sportster and didn't have any issues, but I only put about 30K on it before I sold it to some beaner in El Paso.

Please enlighten me/us?

Again, its entirely dependent upon the degree of rust. If you have a tank that has had water sitting in it (bad gas, tank left open, whatever) and the rust has made serious inroads to the integrity of the tank like the one I screwed Walt over with Walter did a repair and write-up on this last fall, then the Kreem is about the only alternative other than disassembling the tank and rewelding new sheet metal into it, as he did. But for a tank that just has some pitting or a light film of rust, I prefer to just keep it in use. You know how some of your old tools will take on some rust in the handles and contact areas where the plating/coating/paint has worn away....and if you use them once in a while that doesn't occur? Same for the tank. Having gas in the tank that's occasionally agitated by the movement of the bike is the best rust inhibitor. The gas leaves a film on the surface it contacts that prevents oxidation whether the process is already started or not. Remember that the inside of a tank isn't just bare metal, but metal that's been coated or treated for rust prevention by a variety of proprietary processes such as galvanizing or forms of clearcoating shellac. If that coating is breached and the oxidation process is started, it can tunnel underneath the sealing outer portion of the surface, especially if its left to itself.....as when you cover it over with a sealer that's not an integral part of the metal...like Kreem.

So...I'd rather have a lightly rusted tank than a Kreemed tank because----

*Its very difficult to get the process right. The tank has to be completely treated, absolutely dry, and no new rust forming before the coating is put into place. Then the coating has to be properly applied and cured in the correct time frame so that its not too thin, Then the bond at all the openings...filler neck, petcock nipple, and vents has to be perfect or theres an opportunity for air molecules to get down behind the Kreem. If the tank has a molecule sized porosity, air can get in from the outside of the tank as well. Essentially, once you've Kreemed the tank, you have no way of monitoring, maintaining, or repeating your anti-rust regimine....you can only hope it holds.

*A bike is more valuable to me if I can see what the damage is rather than having it covered up, and not knowing how bad it is. When I appraise a vehicle, a rusty tank will probably score higher than a coated one in the absence of other indicators (overall condition, quality of restore, history and pictures).

*A tank with cured rust that has regular use and replacement of the gasoline in the tank is being constantly treated, and the oxidizing process is essentially halted. Of course, the process has already started and is ready to resume its course of damage if uncared for. A good and proper Kreem treatment on an intact tank will virtually halt all continuation of oxidation due to lack of oxygen, but I believe there's significant opportunity for a poor coating to occur simply because of the complex nature of the process.

With a rusted tank, I usually put a couple gallons of a chelating agent into the tank and let it sit for a day where its warm. That leaves a rust resistant coating on the metal once it converts the rust to free iron and oxygen. After that the gasoline in the tank acts as an oxidation inhibitor. Plus I don't have to deal with storing, using, or disposing of an acid. I use Evapo-Rust, available in many hardware stores and even Harbor Freight. Just don't use it on guns, as it can remove bluing.

Sorry this is kinda long and rambling. Post holiday mind-warp, I think.

[texasplumr]

Thanks everybody, I think I'm going to leave it alone. I very glad that I asked first!

Russ