First Subtle Signs . . .

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Aug 28, 2009
What are the first/subtle signs that ethonol might getting past the tank's epoxy liner to where dissolved fiberglass resin is just beginning to contaminate the gasoline ?
Just a few small lumps under the color on the tank. You may also see a darker than normal stain on the carb bodies from tickling the Amals if you run those. Any stickiness of the carb slide or slides.
I had the tank interior epoxied this summer after a 12 year hiatus and also installed brand new AMALs so I've been in hog heaven since then... certainly none of the more dramatic problem signs. But I also had had the ticklers "stick" on me over the last coupla days before they would break loose and operate normally... Hence my question. (The fuel's been sitting in the tank for about a month since I haven't been able to get in more than about 60-70 miles in during that time.)

So I drained some of the tank this evening into a polyethelene "salsa cup" like you get at a fast food/Mexican place (and what I use all the time to mix small amounts of epoxy) to compare to new fuel from the pump.

New fuel is clear.
Tank fuel is pale urine color.
Bad juju.

Worse.... both fuels literally ate through the bottoms of those poly salsa cups in about 4 minutes.
Really bad juju. :?

I guess even Caswell can't handle sitting fuel for a month.

Anyone here know where I can conveniently get non-ethonol'd racing fuel or AVGAS in the Northern Virginia - Fairfax/Dulles corridor ?
I had a glass tank which was red in colour and the fuel was leaving a red stickey residue in the carbs.
Second sign was the thing wouldn't idle, clean the jets and it was good for a day or two. Then same again in a couple of days.
I found Hirsch Gas Tank Sealer very good. Avoid POR 15 in glass tanks.
Maybe you could try one of the airports, I understand the aircraft fuel is not ethenol-ated, but it may be very high octane, which should not matter. the boat people have this problem too and maybe the boat pumps have non- ethenol gas???

I would like to know too, I have not treated my f/g tank yet.

69 S
I have found that eventually your fiberglass tanks will fail from ethanol with any coating - OK i know some peeps will swear "i've had mine caswelled for 2 yrs etc blah blah blah" - i was one of them too - but regardless of many multiple coatings etc my tanks eventually succumbed to the shit they pass off as fuel now days-
best advice- get a steel or an alloy tank - you'll save yourself lots of grief, multiple paint jobs will be spared, and you bike will run better (that melted/liquidized fiberglass will coat your entire intake system and gum it all up)

What are the first/subtle signs that ethonol might getting past the tank's epoxy liner to where dissolved fiberglass resin is just beginning to contaminate the gasoline ?

Once California went to ethanol blended fuel a couple of years ago, I started seeing what looked like orange peel in gel coat of my red fiberglass roadster tank. Prior to this the surface was like a mirror. Even before this I thought I had taken preventative action by having Ken Armann (well known shop in Campbell, CA) coat the inside of the tank. I had to give in and replace with a steel tank.
I was at a bike show yesterday, where there were about 80 bikes, among them 8(!) Nortons. 4 Nortons had 'glass tanks, and every one of them had sealer issues.

Bikes were:
'75 Black MkIII electric start Roadster - fine
'75 R/W/B MkIII Roadster - fine
'75/4 Mongrel w/ Dunstall 'glass tank (bubbling)
'73 Roadster (mine)
'72 Hi-Rider w/ 'glass tank (Caswell bubbling on the inside)
'72 Combat Roadster w/'glass tank (mushy on the bottom)
'71 Roadster w/'glass tank (bubbling)
'56 Dominator 600 - fine

There were also a handful of BSAs there (all A10 and A65), but all with metal tanks.
I have a 1968 BSA Shooting Star with a glass tank that was sealed years ago with what I think was Casswels. It's in constant use & still solid, no leaks and the coating inside is hard as a rock with no peeling issues. My radiator guy has a system of gently bead blasting inside with small tools and nozzles to remove all loose stuff and than he coats the tanks and uses the little nozzles to vacume out the extra stuff so it is a clean nice coating without the big puddles which will crack and lead to gas getting through. I really think most people just can't do a good enough prep job before they coat tanks. Well that's what I hope any way as I'm getting ready to have a Dunstall tank done and am looking for another Dunstall to use with my 850. Any one have a smooth sided Dunstall or Production racer style tank for sale?
I agree with Mik. There are a couple one part sealers that are faily resistant to alcohol but they will not bond to fibeglass for long no matter how they are prepped. And all of the two part polymer based rosins and tank coatings have one thing in common, the correct solvent is alcohol. If you live where alcohol is common in the fuel it is just a matter of time. Jim
Now this is just an idea. It may not be practical at all. What if you cut the bottom out of a fiberglass tank and lined the inside with thin aluminum, I'm thinking now of something like roofing flashing. Sealing it in and back up you'd need something like fuel proof Epoxy. It would probably be easier to mold Epoxy around the filler spout, then a good layer to bond the tank back together.
Anybody got a comment? Years ago I broke down and bought a steel tank for my Roadster (at TT Motors for you local guys) as i was sick of problems from my glass one that had a couple of crashes on it by then.
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