Gas tank

[jeff gibson]

My 125 six day gas tank just started leaking from bottom seam how or what is the fix when I poured the gas out there was a lot of what looked like plastic or some kind of coating came out please help this is a nice bike and need it fixed

[thrownchain]

Ethanol gas?

[jeff gibson]

Yes 93octane

[JCHubbard]

Jeff,

This is a very timely topic. For nearly half of the day, I've been researching tank sealer failures. Specifically, Caswell tank sealer. I've treated 6 tanks with Caswell and only 2 have held up.  The tanks that held up were from 72 Ossa Pioneers, which just happened to have vented gas caps.  As a matter of fact I never even had to drain the tanks!

The failed fiberglass tanks were from a Rokon, 78 KTM (with enduro tank), and 2 Maico coffin tanks -- the one thing they all had in common -- none of them had vented gas caps.  Even after I drained them I noticed some time later that the sealer was cracking around the gas filler hole.  Today, I realized that it was probably gas vapors combined with heat from the garage during the summer, and a non-vented cap that led to the demise of the tank sealers in my case.  

Earlier today, I painted a Caswell treated fiberglass tank for my 74 Rokon 340.  It was treated about 6 months ago and has had plenty of time to cure.  Nonetheless, when I drain my tank after my next ride on it this weekend, I'm going to make sure that the gas cap is not tightened, thereby mitigating the build up of heat, gas vapors and another premature sealer failure.

Later this fall, I'm going to call one of my local body shops that I frequently use to restore my metal gas tanks, and ask if they can open up my failed fiberglass tanks, peel off the damaged Caswell liner and reglass the tanks.  If they can't do it, I'm sure they'll know someone who can.

I apologize for being long winded, but this topic has been swirling around my brain for most of the day. Look forward to hearing what others have to say on this topic.

[JCHubbard]

Interesting article on fiberglass tanks in the boating world:
http://www.boatus.com/seaworthy/fueltest.asp

[Andreas Piepke]

I used Caswell sealer on a 1973 Norton fiber glass tank. It lasted for about one year before the methanol gas destroyed the tank. Success or failure with Caswell may have to do with how well you've cleaned the interior and whether or not you've coated the tank in its entirety. Unfortunately you can't tell as you can't look inside. I won't try this again.

Andreas

'73 Penton Hare Scrambler
'73 Norton Commando
'77 Maico 440 GS

[KJDonovan]

JC, Great article thanks for posting!  I will add that I have has success with the Caswell Dragons Blood product on Penton, Montesa and Bultaco tanks.  I have used it on a more than a few with no failures.  That stated, as part of the prep I also include an additional step of an argon purge after the tank has been cleaned to completely remove any residual moisture.  Additionally I apply 2 coats and avoid fuels with ethanol as much as possible.

Thanks,

Kevin

[jeff gibson]

If I use the caswell tank sealer what would be the best way to clean the in side thanks for all the help

[t20sl]

JC:
Non vented gas caps??  If the cap isn't vented there has to be a vent hose somewhere.  Many caps are vented underneath instead of with a hose or pin hole coming off of top of them.  If there is no vent bike will run for only a short time and then fuel stops flowing.  I believe your hypothesis is flawed.

Ted

[lksseven]

quote:Originally posted by jeff gibson

If I use the caswell tank sealer what would be the best way to clean the in side thanks for all the help

I had trouble a few years ago with sealing a fiberglass 1974 6day tank.  The sealant started fluffing off.  Finally decided that the problem was I had been previously using synthetic oil in the gas mixture - synthetic being much more slippery.  When the tank was prepped for resealing (can't remember who did it - I was one step removed from the process), apparently the inside surface wasn't de-lubed enough due to the higher lubricity of the synthetic oil.

At least, that's how I remember the final conclusion reached.

Larry Seale
I choose to ride...slower and slower all the time

[Kip Kern]

To date, after 40+ years of playing with bikes, I have never heard/seen any tank sealer working on any type of tank steel or fiberglas.  Best thing to do is never leave any fuel in the tank when done riding and having the machine sit. Hope someone out there can prove me wrong but I really doubt it.

[Mick Milakovic]

So, if a tank and has been treated and the sealer begins to flake off, what is the fix?  I believe someone here was going to cut the tank open, clean it out, then basically rebuild the tank?  I would like to hear a step-by-step process if that is the case.

Mick

[t20sl]

Kip:
I have used Red Kote on 2 steel gas tanks.  One is a 1979 Honda CBX.  Was used only as a preventative measure and it has been 8 years plus.  Gas is left in bike all the time.  Sometimes 100 octane no ethanol and most of the time regular pump gas.  No ill effects at all.  Other bike is my wife's Yamaha 650 with same good results and it has been over 18 years with regular pump gas.  I do not drain gas in winter just use a little Stabil or 2 stroke oil mixed in.  Best thing about Red Kote is if it fails just rinse it out with acetone and re-install.  Never had to do it but manufacturer says it is thinned with acetone so seem it would work.
My prep procedure is as follows:
Clean tank with acetone. Soak with hot water and 1/2 cup iron out over night.  Rinse completely with water.  Pour in some acetone to remove water.  blow in warm air until dry and immediately coat with Red Kote.  Let dry for at least a week.

I have used this on several other tanks but they have never seen fuel since coating but would expect same good results.  As far as fiberglass I have zero knowledge.
Ted Atkinson

[Dale Fisher]

I guess I'm lucky to have several local stations that sell race gas and one that sells recreational fuel.  The recreational fuel is Sunoco REC-90 and is 90 octane non-ethanol.  I still drain the tanks and avoid any lengthy exposure though.

Aside from the tank issue I have seen even with the non-ethanol a powderish residue forming in the float bowl area of the carburetor(s) with the potential to gum up the jetting and passages.

What ever happened to the old days of just pour and go [?]

Dale Fisher
Penton Owners Group - President/Memberships
POG Merchandise
Mudlark Registry
Facebook - Penton Owners Group - Administrator
Facebook - Cheney Racing Group - Administrator

[Richard Colahan]

Ah yes...the complexities that arise when using food crops to create a solvent to mix with gasoline...

> I use Caswell in my Norton 750 F/G tank.
Read and FOLLOW the prep directions...that is the key.
Because I use it for general road riding I use pump E-10, but I drain the tank and the carb if the bike is going to sit for more then a few weeks...and I leave the cap flipped up.
Needless to say, it's drained and dried when stored for the winter.
I did have some flaking around the inner diameter of the cap tower, but was able to reseal it.
Despite all of that...I'm sure the day will come when I'll have to spring for a repop steel tank.

> For ANY 2 stroke race or trail bike, or any race bike with a F/G tank, I strongly recommend an E-0 race gas. I use VP Vintage...either leaded or unleaded...about 96 to 98 octane. There are similar products, usually sold in 5 gal cans.
Expensive? I guess...but cheap compared to potential engine detonation or rotting of expensive F/G tanks or read petals...

Richard Colahan
1969 V1225
Upper Black Eddy PA