cleaning and lining the gas tanks on a 1985 honda vf750c...

CLEANING AND LINING THE GAS TANKS ON A 1985 HONDA VF750C V45 MAGNA.DOC JUNE 4, 2012

Z:\Data Files \Motorcycle\H onda Magna (1985) VF750C\Gas Tanks\Cleaning and Lining the Gas Tanks on a 1985 Honda VF750C V45 Magna.doc

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Cleaning and Lining the Gas Tanks on a 1985 Honda VF750C-E V45 Magna

Immediately after I bought my latest bike I did the standard things like

changing out the fluids and filters so imagine my shock when I found this just a few months later.

Not too long after this discovery I made another…..

….. a ‘munged up’ set of carbs

that clearly show that fuel fil ters will not contain the effects of rusty fuel tanks. All fil ters are rated as to the

smallest size particle that they will capture. They allow all particles smaller than this to pass – and obviously, there are many rust particles smaller than

whatever this filter was rated at.

Fortunately, it was now winter in Canada so I wa sn’t losing any road time, and

I’m just tough enough to work in an unheated garage so off came the two fuel tanks.

Now, we all know that the main tank comes off easily enough so how hard could it be to

get the auxil iary tank out? You can see it right there under the left side cover so it

can’t be too tough right? …..NOT!

That tank is inside the frame and as far as I found, the only way it comes out is to

remove the fender and inner fender (which means a ton of the electrics) for starters. By

the time the tank will come out nearly the entire back of the engine is bare!

Believe me this is a job that you don’t want

to have to do twice. In truth, I didn’t want to do it once and the only reason I had to is

that the PO of my bike had figured out how to have the bike start easily in the spring –

drain all the gas in the fall and store it with the tanks dry, then put fresh gas in it in the

spring. Brilliant if all you care about is an easy start in the spring so you can quickly

sell the bike to some unsuspecting dupe like me.

With the tanks out I started an internet search for solutions to my problem. Naturally there were lots of references to the Kreem product – some of them positive and some of them negative. There were warnings about the ‘new gas’ and

how recently introduced additives being incompatible with some of the older coatings.

I contacted the engineering and technical services department of a manufacturer of a cold galvanizing compound to see if that was an option – nope, it would work for a while then be dissolved by the gas (and likely deposited in the

carbs where it would no longer dissolve, naturally).

A. R. MACPHEE JUNE 4, 2012

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The Electrolysis Method

I came across a technique used by restorers of antiques to reverse and stop rusting using an electro-chemical reverse plating process. Sounded perfect and the price was right – a box of washing soda, some water, some garage scraps

and a few hours of electricity.

“Electrolysis is a technique for returning surface rust to iron. It uses the effect of a low voltage electric current and a suitable electrolyte (solution). It has advantages over the old standbys, like vinegar, Coke™, muriatic acid, Naval Jelly,

wire brushing, sand blasting. These methods all remove material to remove the rust, including un-rusted surfaces. With many, the metal is left with a “pickled” look or a characteristic color and texture. The electrolytic method removes

nothing: by returning surface rust to metallic iron, rust scale is loosened and can be easily removed. Un-rusted metal is not affected in any way.” Author: Ted Kinsey at www.stovebolt.com

The basic idea is to physically remove the significant rust chunks then place a sacrificial anode inside the tank, fill the

tank with the appropriate electrolyte solution and use electricity to convert molecules of rust into something that isn’t rust any more. Makes sense right?

I started by dumping a bunch of nuts and bolts into my tanks and shaking it like a maraca to beat the rust chunks off

the inside of the tank. Rinse with water, and repeat several many times until the rinse water runs fairly clear. Then try to tip out the nuts and bolts – not so easy on these tanks with an inlet tunnel. By dangling a magnet on a string a few

dozen times I finally had all the nuts and bolts out (at least they didn’t rattle any more).

Now I was ready to start the magical lead-to-gold process that was going to rejuvenate my tanks for a pittance and make fools of those that paid for multi-part chemical treatments. And now I ran

across an American-Canadian-separated-by-a-common-language-and-culture issue – WHAT THE HECK IS WASHING SODA that’s called for to condition the water??? After some searching I

determined that the closest Canadian equivalent was a laundry stain remover.

I mixed 1 Tablespoon of washing soda per gallon of water and filled the tanks to the top with the mixture. Stronger solutions do not accelerate the process and a re just a waste of soap.

To make the sacrificial anode (the positive terminal) I needed something electrically conductive that would not short to the tank walls

while being jammed roughly into the main tank or dangled easily into the auxiliary tank. Since the electrolysis effect is strongest near the

anode it will be necessary to be able to move the anode around to all areas inside the tank. I used plastic sprinkler hose and punched holes

into it every 1/2:” then fed a chain into it and zip tied it at the bottom so I could pull it tight at the top to ensure conductivity from link to link. You

can see it half completed in the picture – half the chain length is in the hose. The other end of the chain has a wire attached to it that will be

used to pull it into another identical hose. One hose will be located on each side of the tank for maximum anodic coverage of the inside of the

tank.

Inserting the anode into the tank through that inlet tunnel was relatively simple. Removing it was more difficult as the sharp edge of the bottom of the filler neck tended to bite into the plastic and jam it – but all it required was persistence.


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The tank itself is the cathode and the negative wire was attached to one of the mounting screws for the gas cap on the main tank.

The auxiliary tank was hooked up in the same manner with the negative

lead hooked to the tank body and the positive lead to the suspended anode.

The 12VDC power was provided separately to each tank using a 12VDC power supply and a 12VDC battery charger with the overcharge protection circuit bypassed. Without bypassing this circuit the charger will not work as a power

source for electrolysis.

During the electrolysis process the detergent and water solution constantly bubbles and overflows foam from the tank. While this looks alarming it did not damage the paint – possibly because I waxed both tanks to help protect them. The bubbling is caused by the water being cracked into its

hydrogen and oxygen components – a combustible gas and one that supports combustion so no smoking!

Also during the process the anode gets covered in the rust that is driven off the tank wall by the flow of electrons and the solution turns red and muddy. After 24 hours I drained and rinsed the tanks then replaced

the solution with a fresh batch.


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After another 48 hours and one more solution change, I drained and rinsed the tanks then dried them thoroughly using a paint stripper heat gun and a shop vac. Rather than return the tanks to the

unheated garage, I stored them beside the furnace in my warm and dry basement. The next day I went to appreciate the excellent job I had done – only to find that the entire visible inside surface of both tanks was covered in rust again! The electrolysis process leaves a surface that is very susceptible to rusting and I had not protected it sufficiently either by filling the tanks with gas or by oiling the tank walls.

I reasoned that if the tank had developed a heavy coat of flash rust under favorable conditions, it would likely rust in service again and I wanted another solution.

The Vinegar, Coke™ or Muriatic Acid Method

As described by Ted Kinsey, all these methods use an acidic liquid to remove material from the tank walls and they will remove both sound material and rust indiscriminately. This material removal thins the walls of the gas tanks and

leaves behind a surface that is highly prone to re-rusting unless it is immediately and continuously protected.

Since this method structurally weakens the tank to some and in extreme cases could produce leaks if the rusting was severe enough, I wanted another solution.

The Kreem or RedKoat Methods

Both Kreem and RedKoat coat the interior of the tank with a thick latex or latex-like substance to seal the tank. With both products the tank needs to be to be treated to remove the surface rust and gasoline varnish/gum. Internet

research produces both stories of praise and condemnation for these products. But too many users have complained about the product breaking down after a number of months or years, flaking off and clogging the fuel system & carbs.

These failures have been blamed on improper surface preparation prior to the application and/or on the ethanol content of modern gasoline blends.

Since this method has some likelihood of causing significant future problems, I wanted another solution.

The POR-15 Method

The POR-15 system uses a combination of three solutions to clean, activate, and then seal the metal surface. Marine Clean removes any grease, oil, varnish, rust, and gasoline residues from the tank surface leaving an alkaline surface.

Metal Ready prepares the metal surface to receive the POR-15 epoxy based sealant by changing the alkaline surface to an acidic one that the POR-15 can stick to.

Three thin coats of POR-15 are recommended for optimal results and the timing of the application of subsequent coats

is important. The second and third coats should be applied when the previous coat is tacky but almost dry. If the previous coat is fully cured, wet sand first with 600 grit sandpaper until gloss is dulled – this is what makes timing

important since this is essentially impossible inside a motorcycle gas tank.

Drying time depends on the humidity. The more humid it is, the faster the drying time, which usually varies from 2 to 5 hours.

More information and instructions are available at www.por15.com or www.caswellcanada.com.


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The steps for applying POR-15 are:

(a) Clean the large pieces of rust off the tank walls and remove them from inside the tank. The nuts and bolts method will do fine.

(b) Rinse the tank with water. (c) Wrap the tank completely with plastic wrap (i.e. Saran wrap), then

aluminum foil, then plastic wrap again to protect the paint from any spills. (d) Tightly seal all openings with removable plastic caps or rubber plugs,

held in place with duct tape. (e) Mix the marine clean with a quart of very warm water and pour it into the

tank. (f) Reseal the tank and shake and roll the tank around for 20 minutes to

ensure that the marine clean gets to all the internal surfaces of the tank. After the initial shaking, I mounted my tanks on a BBQ Rotisserie that

would do the turning for me. Periodically I tipped the rotisserie from one side to another to ensure even coverage down the length of the tanks.

(g) Empty the tank and rinse it with water. (h) Once the tank is drained but not necessarily dry, pour the metal ready

into the tank. (i) Reseal the tank and shake and roll the tank around for 20 minutes to ensure that the metal ready gets to

all the internal surfaces of the tank. Do not allow the metal ready to be in the tank for longer than 2 hours. (j) Empty the tank and rinse it several times with hot water.

(k) Once the tank is drained it must be thoroughly dried using forced air and a heat gun. This is a critical step as the por-15 will not stick to a wet or damp surface.

(l) Open and stir the por-15 until it has a uniform colour then use a scoop to remove 4 ounces and pour it into the tank. Immediately reseal the por-15 can using plastic wrap between the can and lid to make sure it

can be opened again later. Por-15 is a thin l iquid with the same consistency as water and it will flow into cracks and crevices very well.

(m) Roll the tank slowly, ensuring that the entire inside gets covered, checking occasionally to determine when it is time for another coat to be applied.

Plastic Wrap Aliminum Foil Second Plastic Wrap


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There is a small vent tube that runs under the entire length of the tank, enters the tank bottom, and terminates near the

filler neck. I used a length of house wiring to make sure the ¼" vent tube didn't get plugged with POR-

15 (needed ONLY during the use of the sealer). Need about 24" - strip the outer insulation off and select either the black or white coated solid copper wire - leave the insulation on. Lay it alongside the

vent and mark the total length needed to have the tip just enter the tank. Put vaselene inside the vent tube and start pushing the wire in. Occasionally add vaselene but try to keep it off the wire outside the tank because you need to be able to grip it and force it in. It is possible to work the wire all the way in. Use the sealer and once you have the number of coats you want, pull the copper wire out.


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Making a Tank Turner

To make my tank turner I started with a standard BBQ rotisserie and built a simple wooden frame to mount it on, making sure that the wooden sides were far enough apart that the tank could pass between them, and that they were

long enough that the tanks would clear the cross bar.

As it is a temporary fixture there is nothing fancy about it. The spit hangs in a metal strap under the end of each of the side 2x4sand the motor is zip tied to the outside of one leg. The entire fixture is mounted on a cord that runs from

each end over a centre support that is hanging from a ceiling beam. This cord and centre support allows the entire fixture to be tilted towards either end. I kept the entire fixture low to the floor to minimize any damage should a tank fall

out of the fixture.

I used an empty spool of industrial welding wire to mount the two tanks on. I cut the wooden sides of the spool to

match the profiles of the two tanks and held the tanks on with bungee straps. I tried to balance the spit by keeping the main tank tight to the spit and setting the smaller auxiliary tank further out. I drilled 4 holes and used the rotisseries’

meat mounting hooks to secure the spool to the spit.

Since the rotisserie motor is not very strong it was necessary to adjust the balance of the two tanks depending on what

was inside them. In this picture you can see several bolts acting as ballast under the green bungee cord.

cleaning and lining the gas tanks on a 1985 honda vf750c...

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