Ethanol-proofing a gas tank

[Luke]

I recently bought a Scorpa trials bike. It's a great bike but it was made in 2001, back before most gas had ethanol added to it. The tank was made of some sort of plastic or fiberglass that was dissolved by the ethanol and would gum up the carburetor. I was warned by the PO about this, and was told that if I ran regular gas I would need to drain the tank every time I used it. Annoying, but tolerable. After riding it a while, I discovered that the problem was worse than that- the carb would gum up before I could even finish a tank of gas.

My options were:

Buy race gas. At $65 for 5 gallons, not going to happen.

Buy non-ethanol gas. I don't want to drive around to marinas to find gas, and the last place I went to that sold non-eth was 150 miles away and wanted an extra $1 per gallon. No thanks.

Fix the tank. This is what I did.



After a bit of on-line research, I ordered this kit from Caswell Plating. http://www.caswellplating.com/aids/epoxygas.htm It was about $50 with shipping. A bit spendy for a tub of glue, but it's about the difference in price between 5 gallons of race gas and regular gas, or the cost of two trips to a marina. In other words, it's a bargain. I had no proof that the epoxy would stick to the plastic of the tank but I figured that since paint stuck to the outside it would work.

Here's the start:



I also used electrical tape and plastic food wrap. I did not use the scale. I would not recommend using the foam brushes- use a paint stirrer instead. The instructions are good. Read them. Repeatedly.






First get the old gas out using acetone, I used the whole pint. It's a really good idea to wear gloves. Latex is impervious to acetone, not all rubber gloves are.





Then wash the tank out with detergent and hot water and let it dry.





Next wrap the tank in plastic and electrical tape to keep the epoxy off the outside.





The idea is that you're going to fill the tank with epoxy, seal up the openings, rotate the tank to get the epoxy on all the surfaces, then open the top and drain out the excess. After the epoxy starts to cure it'll get rubbery. Uncover the petcock hole and cut the excess epoxy away with a knife so that the petcock will fit in.


If you fold some of the tape back on itself to make a tab, it's easier to remove.


I don't have a picture of how I covered the top of the tank, but it's pretty easy. Just use a rubber band and some plastic. I didn't have a rubber band, so I cut the wrist of one of the latex gloves.


Mix the epoxy. If you're doing several tanks at once or one big one, just dump it all in. I mixed half of each container. If you do mix half, it's important to get the ratio correct, or the epoxy won't cure properly. Unfortunately, I have no idea how close the ratio has to be.

I was a bit busy to take pictures of the next part. After mixing the epoxy, pour it in the tank, cover the top, and shake it around, rotating the tank in every direction you can for a few minutes. Then take the cover off the filler cap and set the tank so the epoxy will drain out.



Hot tip: figure out how you're going to set the tank to drain before you start messing around with the epoxy, not after.

After about an hour, remove the tape that's over the petcock hole and trim up the excess epoxy. Let the epoxy cure for a few days. After it's done, clean up the filler neck. This is how it looked before cleaning it up.




Finally, assemble and ride!






I did this about a month ago, and it's worked really well. I have used regular E10 gas, never drained the tank, and have had no carb troubles at all.

[gweaver]

I'm very intrigued by this. I was talking to someone about the Safari/Aqualine tanks, and the fact that for the 950/990, they tend to 'shapeshift' which makes putting them back on challenging. He mentioned that the CA ethanol gas may contribute to that. If this product works and solves the deformation issue, there may be a set of those tanks in my future!!

G

[Luke]

Originally Posted by gweaver

I'm very intrigued by this. I was talking to someone about the Safari/Aqualine tanks, and the fact that for the 950/990, they tend to 'shapeshift' which makes putting them back on challenging. He mentioned that the CA ethanol gas may contribute to that. If this product works and solves the deformation issue, there may be a set of those tanks in my future!!

G

Since Aqualine is still in business (unlike Scorpa) I'd ask them what their tanks are made out of, then ask Caswell if their epoxy will stick to it. The Aqualine tanks I've seen seemed more like HDPE, which nearly nothing sticks to.

[motojunky]

Please keep us updated over time. I was/am/maybe considering this, but got scared by a couple of articles I read where the epoxy didn't hold up in the long run. It'd be nice to be able to buy fuel at the corner station for reasonable money.

[ridenm]

I've noticed that older Sherco tanks (think '02, '03) seem to develop crazing around the petcock area that eventually weeps fuel. I wonder is ethanol blends cause this? And I wonder if this epoxy product will work on whatever plastic the Sherco tanks are made from?

[alainmax]

hi Luke,

great write up

i have a scorpa 2006. not sure what the tank is made of...

could you comment on the symptoms you had before doing the mod.
I wonder if that is the reason mine doesn't want to start or when it does run, going downhill seem to kill the engine( it just dies...)??
I'm in Portland

thanks

[Luke]

Originally Posted by motojunky

Please keep us updated over time. I was/am/maybe considering this, but got scared by a couple of articles I read where the epoxy didn't hold up in the long run. It'd be nice to be able to buy fuel at the corner station for reasonable money.

Will do. I put the liner in a couple of months ago, and it actually sat all September with gas in it; I only ran the float bowl dry before putting it away. It ran fine today. So I consider it a great success- for now.

Do you remember where the articles were or what their problems were? I'd like to know what to keep an eye on.

Originally Posted by ridenm

I've noticed that older Sherco tanks (think '02, '03) seem to develop crazing around the petcock area that eventually weeps fuel. I wonder is ethanol blends cause this? And I wonder if this epoxy product will work on whatever plastic the Sherco tanks are made from?

I couldn't really say. Unfortunately if the epoxy doesn't stick you'll have a big mess on your hands. An alternate solution might be to use a plastic welder or soldering iron to melt the plastic back to shape. That's also potentially a big mess.

Originally Posted by alainmax

hi Luke,

great write up

i have a scorpa 2006. not sure what the tank is made of...

could you comment on the symptoms you had before doing the mod.
I wonder if that is the reason mine doesn't want to start or when it does run, going downhill seem to kill the engine( it just dies...)??
I'm in Portland

thanks

Your symptoms sound just like mine. The pilot jet gets plugged and it won't idle. It will run if you constantly give it throttle.

It isn't necessarily this tank problem causing it. Any other gunk in the carb will cause the same problem. When I opened the carb up to clean it out there was a bunch of white powdery residue in the throat and the float bowl, and the pilot had clear goo in it.

I don't know if the '06 has the same tank as the '01, but the '01 tank really felt bad. I could feel a gooyness when I rubbed my fingernail on the inside of the tank. Not like any other kind gas tank or can at all.

I'm in Beaverton; I'd be up for taking a look at your bike (I also want to see how the gas tank attaches on your bike. Mine's missing a few bolts)

[alainmax]

thanks for the info Luke,

Im in west linn, I'll PM you my cell number
d'be happy to meet you

[bomberdave]

i used caswell on my tank and its held up great. im pretty sure you could make a paper tank and line it with the stuff and it would hold gas just fine.

tip- try to do this in a warm enviroment, i did it in a cold shop and it kept the stuff from getting liquid enough, i used some soft heat on the tank to get it flowing again.


tip- next time i do this im going to use some modeling clay or something around the filler hole to get the edge the way i want it- it took a bit of work to get the gas cap working right.

[motojunky]

Originally Posted by Luke

Do you remember where the articles were or what their problems were? I'd like to know what to keep an eye on.

Not motorcycle related at all, but it was the article below that got me worried initially. After I got looking around, most of what I found was boating related since fiberglass tanks are much more common in that environment. If you follow the link at the bottom - and again on the 2nd page, you can see his issues with ethanol start to finish. In a nutshell, he used a sealer (also from Caswell - maybe the same product?) that claimed to be ethanol proof and it just plain wasn't.

http://www.egyptian.net/~raymacke/Cbnskif17.htm

[ChromeSux]

Originally Posted by bomberdave

tip- try to do this in a warm enviroment, i did it in a cold shop and it kept the stuff from getting liquid enough, i used some soft heat on the tank to get it flowing again.

Local motorcycle painter who is real good uses Caswell inside all the tanks he does, tells me he warms the two cans up on the stove eye before mixing (lids off the cans of course).
I tried it last time i used Caswell and it worked, stuff flows much better.

[tjhess74]

this may help also, depending on what state youre in. easier than finding a marina or buying epoxies for your tank...
http://pure-gas.org/

[mubikS]

I run a marina / boatyard / non-ethanol gas dock, so my two cents:

Ethanol has created big problems in the marine environment too. First, it was with the old polyester-based fiberglass fuel tanks. The ethanol (an alcohol) would degrade the poly resin and cause just the same problem you experienced... an nasty, gummy substance in the carbs. Second, it binds to water more readily than fuel, and a small amount of water in the tank (~2%) would cause the ethanol to separate out of the gas. Again, a nasty gummy substance.

I sell more non-ethanol to folks with five-gallon cans filling up their lawnmowers than I do to boats lately.

[motojunky]

Originally Posted by tjhess74

this may help also, depending on what state youre in. easier than finding a marina or buying epoxies for your tank...
http://pure-gas.org/

Unfortunately, not if you live where I do. Not a single ethanol-free station around according to that website and lots of searching on my own. I'm less than 10 minutes from several marinas and all have ethanol in their fuel.

I have a dragstrip and a VP dealer relatively close by, so getting fuel isn't really a problem, I'd just rather not pay $9/gal for it. That said, I don't go through all that much fuel on my Scorpa, so it's not really an issue. I ride it 99.9% of the time in my backyard, so I'm not burning fuel in the truck getting to a riding area either.

[Luke]

Originally Posted by motojunky

Not motorcycle related at all, but it was the article below that got me worried initially. After I got looking around, most of what I found was boating related since fiberglass tanks are much more common in that environment. If you follow the link at the bottom - and again on the 2nd page, you can see his issues with ethanol start to finish. In a nutshell, he used a sealer (also from Caswell - maybe the same product?) that claimed to be ethanol proof and it just plain wasn't.

http://www.egyptian.net/~raymacke/Cbnskif17.htm

Thanks for the info. It looks like he was using the same stuff, and it completely separated from the original gas tank. Now I know what to look for with this stuff.

Originally Posted by ChromeSux

Local motorcycle painter who is real good uses Caswell inside all the tanks he does, tells me he warms the two cans up on the stove eye before mixing (lids off the cans of course).
I tried it last time i used Caswell and it worked, stuff flows much better.

It was 85-90 degrees out when I applied it. It flowed really well. It sounds like a great idea to heat them up if they aren't that warm already.