Rusty gas tank filler neck

[Toovalks]

I haven't done much research on this ,but I'm not familiar enough with the Valks. , to know how to go about this. On my "wonderful " Ebay purchase I've found that I have a very rusty gas tank, solid but rusty. Ive dealt with rusty tanks on other motorcycles. I have never had one that had  a neck that stuck down into the tank the way this Valkyrie tank has. So,I've washed it out,put in some screws to shake around and "deflake " it before I acid wash it. The screws are small so they can come out the bottom, but what I would like to know about is cutting the neck out up closer to the inside surface of the tank. I think I read that there is a problem with gas spillage when you fill these  tank. Is it safe to cut out this neck,or is there something that it is hiding that I will destroy if I do this. 

[hubcapsc]

Grumpy posted a few years ago about some de-rust goo that works great
and is not harsh like acid.

Punisher used it in a really rusty tank, and it worked great.

Maybe they'll see this post and remember the name of that stuff.

I hope you don't have to cut up your tank or line it, ick...

-Mike

[Pete]

Done properly it will not destroy the tank.
If you try to cut it to short you will run  into the air breather supply mechanism for the tank.

I can not think of a good reason to cut the filler neck, it is there as a fill reminder to fill to the bottom of the filler neck. I know others have drilled holes in the filler neck to allow them to fill higher into the neck. I am not aware of an reported issues reported with that.

I suspect that the filler neck is there to reduce gas movement against the cap and reduce the possibility that gas expansion thru heat on a full tank will cause fuel expulsion thru the tank air breather line. As well as to allow for the use of the side stand without gas loss when to full.

I see no real need to shorten the neck or drill holes in it.

[pancho]

Hey Tgreer,, that tube looking piece you are looking at, is to keep sploshing gas from constantly washing against the inside of the cap and causing leaks.   I would leave it as it really has a purpose.

 I don't know what you would use to remove it,, seems like it would make a mess.

[longrider]

Look up Kreem fuel tank repair.  I have used it with great success

[da prez]

  I started to do a post and then did some research. I found a couple interesting sites.
electrolytic rust removal , which I will try on our next rusted fuel tank. There was a link to a fuel tank liner. Make sure you choose the correct link.

  http://www. eastwood.com  for the liner product. I think it was about $30.00.  We use to buy a product called red liner ( I think) that worked OK. Be sure to thoroughly dry the inside of the tank.
 
                                              da prez

[hubcapsc]

Here's where to get the stuff Grumpy mentioned:

https://www.evaporust.com/evaporust.html

Allan used it on a rusty tank, and it worked great without being
harsh like acid.

Grumpy mentioned the evaporust stuff when he saw me post
about removing rust with Oxalic acid, which also works great
but is aggressive... I used Oxalic acid to remove rust from
the bottom of a set of triple tips I have, by soaking the tips
in an aluminum pan with Oxalic acid in it. By the next morning
the pan was empty and the Oxalic acid had eaten a hole in it.

-Mike "I'd hate for something to eat a hole in your gas tank..."

[da prez]

  How do you highlight to get a link to post.  Old age inquiring minds need to know and be told again yesterday. 

                                         da prez

[hubcapsc]

  How do you highlight to get a link to post.  Old age inquiring minds need to know and be told again yesterday. 

                                         da prez

I'm not sure how you made that www.eastwood.com link break up like that...
perhaps you just left out the dot between www and eastwood?

I just type in URLs, and the thing that formats our posts recognizes them as
hyperlinks, even if they are bogus...

www.bogusthing.spo

-Mike

[Pete]

Electro de-rust process from Jason. Works great, I have used it on gas and diesel tanks.
Just one warning if the outside paint has a speck of rust under it, It may bubble the paint at that spot.

On  really rusty tank do it twice, the complete process.
 
 
  Jason’s de-rusting method

 Hi all, I've gotten a few requests for the magical gas tank derusting
 process.  Wonder if it deserves space in the faq?

 You need
 1 rusty gas tank
 1 small container of sodium carbonate, chemical compound, Na2CO3 pool/spa supplies PH+
 1 4amp or better battery charger
 1 average bolt approx 3/8 x 1.5
 1 short length of copper wire, ~ 12 awg
 1 qt naptha
 1 qt denatured alcohol

Empty out all the gas, take out the petcock and remove the fuel cap.  Remove  any 
old fuel residue and varnish with a good rinse of naptha, make it
petroleum  free and  then drain / dry.  using a sock with a handful of small
nuts/washers etc, add a little water  and shake this  all around inside the
gas tank to loosen the big chunks, rinse with clear  water scrub well. In a
decent pail (not oil drain bucket), dissolve some of the sodium  carbonate in water,
1/3 cup for say a magna, 1/2 cup for a sabre in a gallon of clear water, 
when its dissolved  all the way stir it a bit more!

Seal up all but the filler cap opening on the top, pour in the well stirred
mix using a funnel if you've had too much coffee.  Fill the tank right to the
top with water,  set the tank so  that the cap opening is the highest part,
burp out as much air as possible  and keep the  tank full for the process.

Wrap a half dozen or so turns of the wire around the bolt to hold it  secure, 
twist it tight  so the bolt won't fall off.  Attach the (-) lead of the batt
charger to  the  outer shell of  the tank, attach the (+) to the other end
of the copper wire, suspend the  bolt in the  solution and turn on the battery
charger to a fairly high rate, an amp or  two flowing is  good, then wait.
Time to process is ~48 hours and it won't overdo itself.


The bolt gets nasty after a day, I cleaned mine now and again  to remove the
crud  but  not  sure it helps.  After a couple days, remove the leads,
discard the bolt, save the wire,   drain and rinse the tank well, drag out
that sock and slosh it all around to remove any loose material. 
Rinse a few more times until the rinse water seems clean, shake well and
then use a bit of the alcohol to fetch out the rest of the water.

Once the tank is dry, you're all set to put it back into service.
More coating not required

Science, maybe remove this junk   The process by which rust forms is
electrochemical in nature so this method employs a reverse current flow
in an alkaline bath at a higher voltage to reverse the process at a quicker
rate. There are actually two forms of rust: iron III oxide or red oxide
(Fe2O3) and iron II, III oxide or black oxide (Fe3O4)(FeO). Black oxide
is a smaller molecule. The electrolytic process converts red rust to
black rust and in the process the black rust becomes weakly bonded to
the base metal. The black rust that takes the place of the red rust can
be easily wiped, washed, or brushed off leaving rust free base metal.
Any pitting that has occurred will remain, this method will not repair damage,
but the pits will be rust free.

This is an alkali process and not acid, so you don't have a lot of pits
in the steel filled with stray hydrogen ions which would just love to start
rusting immediately instead of a much less active coating of black oxide.

 -Jason

[Dale_K]

A couple of videos showing a guy cleaning out a rusty Valkyrie gas tank.

https://www.youtube.com/watch?v=xphC3oy1mwA
https://www.youtube.com/watch?v=hda12k__UWg

This guy has a 9 part series of getting an old Valkyrie back on the road.  Mostly it covers the rusty tank and carb rebuild.  One thing I remember him talking about was the internal tank venting on the Valkyrie and how it was possible to substitute a different Honda gas cap that vented through the cap if the internal vent tube is beyond repair.

[jim@98valkyrie.com]

I recently cleaned a very rusty tank with cider vinegar. Very cheap, very easy. Does take a bit longer.

[Bagger John - #3785]

Look up Kreem fuel tank repair.  I have used it with great success

Up until water gets between it and the tank through a pinhole in the surface, then you're going to have bigger problems.

Use a product like POR-15 which will chemically bond to the tank and add strength to the base metal.

[Solorider]

I  have been working on a 1999 Valkyrie for almost 8 months it was a Hurricane victim....A real mess...Just started it up for the first time yesterday.....OWWWWW the power.....  I had a super rusty tank ... I used the Kreem method ...but had to use 2 kits ..each kit =3 gallon tank ... Also I found my vent tube was rusted through inside the tank, by using air up through small pipe under thank thus I heard air venting inside tank and not the neck vent,  So I JB welded the tube shut at the bottom of the tank and found the new old model Honda Magna gas cap ( Vented ) that matches perfectly to the valk surrounding chrome .. The cap does not leak fuel out either..  It looks like original cap. two keys now...

I posted the model # of cap somewhere on the site before in another discussion on this same issue

Now I have a non working fan, new grips,  finish paint job,  and a ton more work before I ride this machine 

Good luck with rusty tank issue

Solorider