Resurrecting a 38 year old motorcycle

 by knife141
Featured

Step 5: Repairing the gas tank

The gas tank had numerous problems.  First, the inside was rusty and coated with 38 years of gunk.  The petcock was clogged, and the tank had four dents in it.

Using a drill bit as a hand reamer, I unplugged the galleys in the petcock, then soaked it in carb cleaner.

For the inside of the tank, I first put a handful of nuts an bolts in it along with about a quart of degreaser, plugged the inlet and outlet, then rocked the tank back and forth and up & down for about 30 minutes to loosen the crud inside.  Next I used a DIY commercial cleaning coating process which entailed soaking the inside of the tank in a weak acid solution for 8 hours, then using a neutralizer, then a permanent coating.

After taking care of the tank's insides, I then began work on the part that "shows."  I used bondo to fill the four dents, carefully sanding and feathering the filler to the lines of the tank.  Then I applied primer, then paint.

While the finaly coat was drying, I used a small knife blade to scrape away the rust from the tank's logo, then touched up the paint on the logo with an artist's brush. 

Before reattaching the logo, I applied stair tread (sort of like a rough, rubbery tape) to the sides of the tank for decoration, then screwed the logo back on each side.

I realize this is not exactly how the original looked, but remember -- this is a resurrection, not a restoration!
 
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bighamms says: May 13, 2010. 7:44 AM
Can you tell me the name & cost of the system you used for the tanks interior?
milesduggan in reply to bighammsAug 19, 2011. 7:44 AM
Ps. its like $40 but it goes a long way!
milesduggan in reply to bighammsAug 19, 2011. 7:43 AM
Don't use "Kreem" it is terrible! I had to redo my tank because it started to break down. I followed the instructions to the letter. An acquaintance of my told me it doesn't hold up well to fuel which makes no sense to me but I saw it first hand. He recommended a product called "Phenol Novalac" by "Caswell". Look up their website, its a great tank sealer! I used it and am blown away how easy it was to use and the results I got!
knife141 (author) in reply to bighammsMay 14, 2010. 1:08 PM
I used a product called Kreem, purchased at a motorcycle shop.  Don't recall the cost.
milesduggan in reply to knife141Jun 25, 2011. 12:48 PM
I think the kreem is like $20 for just the sealer. Pretty sure the whole 3 step kit is $50(acid wash, conditioner, and sealer).
milesduggan says: Jun 25, 2011. 12:47 PM
Ugh I hate cleaning gas tanks! I am in the process of fixing up a 1975 Honda CB360(got it for $500) and all it needs is a good cleaning(carbs, gas tank, motor) and new fluids. The gas tank is a little rusty inside and I have been procrastinating on getting it done. Well looks like the July 4th weekend is as good as any.
mrlunna13 in reply to milesdugganAug 19, 2011. 3:35 AM
Hello,
did you de-rusted your tank? I had the same problem. My tank was more than 40 years old. no paint, just rust. I did electrolysis on it. It looks awsome!!
You should try that if you haven't already. It really works wonders, and no fumes or harsh chemicals.
Here's the before and after. I just rinsed it with a hose.
my coffin01c.jpgHPIM2571c.jpg
milesduggan in reply to mrlunna13Aug 19, 2011. 7:33 AM
Holy crap! What a difference! I did use the phosphoric acid to do my tank and it worked great, I just looked like a haz mat worker in the process. lol. Great job on your tank! Wish I would have gone your route although my results were just as good, just a little more work.
Bapper23 says: Jul 19, 2010. 7:29 PM
Working on my gas tank this week. 1977 Kawasaki. What did you use to plug the holes before cleaning it with nuts and bolts and liquid? i went to Lowe's to find rubber plugs for the petcock holes and they didn't have any....... Also...... what about the gas cap? Thanks! Rich
knife141 (author) in reply to Bapper23Jul 20, 2010. 6:38 AM
I removed the petcock and made a temporary plate to go over the opening (and sealed it with a homemade cork gasket). I used duct tape to seal up the filler opening. The seal on my gas cap was bad, so I replaced it with a new one off of ebay.
Bapper23 in reply to knife141Jul 22, 2010. 8:03 PM
Thanks! By the way..... Lowes does have a 2 inch plug for the gas tank in the plumbing section. It's rubber with a twist top and plastic on top and bottom. Put it in the tank fuel hole....... tighten the top and works like a charm...... NO leaks (shook it in a plastic bag just to be sure) ----- used Gorilla tape for the petcock holes and also no leaks.... Rinsed my tank out with water then used Purple Power (from Auto zone) with about 18 nuts and bolts..... Tomorrow is step two with a kit from POR15. Three-step bike kit.........
magic1969 says: May 13, 2010. 7:23 PM

  yes i am restoreing a 71 honda rebel i am haveing trouble getting the tank to stop leaking.i have used marine tex,to stop all the leaks but new ones pop back up . there is a coating for the inside but i don't know what it is ,i can't afford a hunderd dollar coating.i got the rest going great. i will show it to you after it is finished. it stayed in the rain for over a year so i had some rust and other problems.like i had to use screen wire to cover some big hole in the tank. now it looks great but ............any advise be nice........

romoshka in reply to magic1969May 14, 2010. 9:14 AM
POR-15 will seal and stop leaks inside MC tanks - i have used it for years - there is another product called KREEM but I have never liked it - POR 15 is a bit more expensive but as they say - "Ya gets whats ya paz for"
magic1969 in reply to romoshkaMay 14, 2010. 12:35 PM
thanks for the infro but what is por-15 called by what brand and where do you buy it??????also kreem?
romoshka in reply to magic1969May 14, 2010. 7:21 PM
oh yea - and stop by your local machine and ask to borrow a couple of cups of their old carbide inserts - promise to return them and offer to sweep the floor and bring a dozen donuts - place these in the tank and place the tank in your dryer - stuff pillows all around the tank to prevent it from banging and damaging the dryer drum - set the dryer on fluff or no heat and let it run for 30 - 60 minutes.  This will ensure that the inside if the tank is perfectly cleaned.  then proceed with the liner (por 15 or kreem)

romoshka in reply to magic1969May 14, 2010. 6:55 PM
google search on POR 15 and Kreem and you will find and be able to read all about them
bighamms says: May 13, 2010. 7:49 AM
Also, are you rattle canning the paint, or do you have a pro setup in the garage?
knife141 (author) in reply to bighammsMay 14, 2010. 1:05 PM
I rattle can'd it.  I'm not set up for a spray rig.
laparsons says: May 13, 2010. 3:21 PM
Where do you get this product? DIY commercial cleaning coating process
blackserpent says: May 13, 2010. 2:05 PM
Which kind of tools do you use to paint ? I would like to restore old bike frames and It would be great to get such results. Many thanks.  ERIC
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