Is 10% Ethanol gas bad for Fiberglass Tank

chasesa · Dec 5, 2009

I filled my '68 Norton Commando tank with 10% ethanol gas while in Maine recently. To that point it had run perfectly over the 5000 miles since re-build on Canadian 91 octane (no ethanol) gas.

I drove home (60 miles) at 70 mph (still running well), got home, parked the bike for a week.

This bike always started first kick, but when I tried to start it it would not start well and backfired. Since then, I have dismantled the carbs to find a sticky dark residue in the manifold & also on the needle.

Questions:
1. If it was the ethanol gas, how can I fix the situation with the tank. I am totally cleaning carbs (as we chat).

2. How can I clean the seeming light gum deposit in the head? Would something like GM combustion chamber cleaner work?

Thanks,
Stephen

maylar · Dec 5, 2009

Bummer. You need to get that gas out of the tank before it seeps through the fiberglass and destroys your paint.

The intake ports can be cleaned with carb cleaner spray (Gumout etc). I wouldn't worry about the combustion chambers. A tank sealer like Caswells Epoxy is in your future. If you can still get gas without Ethanol you're a lucky guy, there's no such thing around here. That's why fiberglass tanks are cheap on eBay and steel ones are very much in demand.

Jeandr · Dec 5, 2009

Carb cleaner or alcohol will be OK to clean the brown residue. Drain the tank and make a big bonfire or Molotov Cocktails with it and refill with new gas, I found Esso (in Montreal at least) is OK on fibreglass. To avoid further problems, line the tank with a proper sealer. I used Hirsh gas tank sealer (see gas-tank-sealer-t4653.html) which seems to work fine so far. When my Commando's tank was damaged and my carb was full of gunk, I only cleaned the carb so it wouldn't stick and didn't worry about the rest.

Jean

norbsa48503 · Dec 5, 2009

Well Jean, I have done the Hirsh thing and I made it two years before it found it's way through. Many have had similar experiences with Caswell's for different reasons. I to thought I had found a solution but to no avail. I would never try to store our new gas for more than a week. Use it or lose it. Sloshing is the problem you just can not be sure you have it right and you will get thick spots no matter what. Thick spots are a problem for Caswell's liner because it is too brittle to withstand being shaken by the motor. It will fail some day keep an eye out. Hirsh's liner seems to be the opposite, thin spots no matter how you clean the tank inside it always seems there are some areas that resist being coated and they may seem to get done on a second coat but they don't, sorry to be so negative but I have found this all out the hard and expensive way.
I am working with a local glass tech to solve the problem it does mean cutting open the tank so it can be ground and hand painted with a thin layer of Caswell's we have to use this instead of Hirsh's because the key is to keep it very thin and the tank must be glued back to a shell when done.So epoxy is necessary might as well use the same product throughout the repair. This is the tricky bit. You have to form a new glass shelf that provides enough surface area to get the strong bond needed. The fit must be very good, cast in place in fact so as to keep the bonding area free from spots that would get too thick and crack. You also have to be very careful to not use too much at the time of the bonding so that squeeze out does not form and provide another thick spot. A difficult process to be sure and it will be reserved for those that must save their tanks for originality purposes. We are going into a cost that will rival an aluminum tank being made. We are starting with a Fastback tank building one from scratch from a stock good old one first.The mold is made and is a work of art that those who have done this work would like to see. Resin that will hold this gas is only available in huge expensive quantities and is a false economy for these old bikes. So the new tanks will be lined because even the vinyl esters will fail but are better than the old way. We are a good ways off from even a testing of these principles so I will try to keep informed as to new info. Watching your efforts with interest though. Now if you really have some money we could make a stainless mold and cast the tanks in plastic. I have such a tank that is B-40 like and it will run 100% alcohol no problem. Cast from the same plastic that they make the bottles that you store it in.

Cookie · Dec 5, 2009

Cast from plastic, that's a fine idea. I had been thinking along the lines of an alloy liner but that would require opening them. Buying a used steel tank seems most cost effective at the moment.

chasesa · Dec 5, 2009

Folks,
I am soaking the tank with Varsol to get rid of the ethanol gas. i then plan to rinse and wash with soap & water then air dry.

Once this is done, SHOULD I BE OK IF USING ONLY NON-ETHANOL GAS?

I have no reason to seal out ethanol gas since there is no ethanol, at least in my part of Canada.
Thanks!
Stephen

swooshdave · Dec 5, 2009

chasesa said:
Folks,
I am soaking the tank with Varsol to get rid of the ethanol gas. i then plan to rinse and wash with soap & water then air dry.

Once this is done, SHOULD I BE OK IF USING ONLY NON-ETHANOL GAS?

I have no reason to seal out ethanol gas since there is no ethanol, at least in my part of Canada.
Thanks!
Stephen

Yes, no problems with non-ethanol gas.

swooshdave · Dec 5, 2009

norbsa48503 said:
I am working with a local glass tech to solve the problem it does mean cutting open the tank so it can be ground and hand painted with a thin layer of Caswell's we have to use this instead of Hirsh's because the key is to keep it very thin and the tank must be glued back to a shell when done.So epoxy is necessary might as well use the same product throughout the repair. This is the tricky bit. You have to form a new glass shelf that provides enough surface area to get the strong bond needed. The fit must be very good, cast in place in fact so as to keep the bonding area free from spots that would get too thick and crack. You also have to be very careful to not use too much at the time of the bonding so that squeeze out does not form and provide another thick spot. A difficult process to be sure and it will be reserved for those that must save their tanks for originality purposes.

If I were to cut open a tank to fix it I'd probably coat the insides with the newer fiberglass epoxy and not go for something like Caswells.

Jeandr · Dec 5, 2009

norbsa48503 said:
Well Jean, I have done the Hirsh thing and I made it two years before it found it's way through. Many have had similar experiences with Caswell's for different reasons. I to thought I had found a solution but to no avail. I would never try to store our new gas for more than a week. Use it or lose it. Sloshing is the problem you just can not be sure you have it right and you will get thick spots no matter what. Thick spots are a problem for Caswell's liner because it is too brittle to withstand being shaken by the motor. It will fail some day keep an eye out. Hirsh's liner seems to be the opposite, thin spots no matter how you clean the tank inside it always seems there are some areas that resist being coated and they may seem to get done on a second coat but they don't, sorry to be so negative but I have found this all out the hard and expensive way.
I am working with a local glass tech to solve the problem it does mean cutting open the tank so it can be ground and hand painted with a thin layer of Caswell's we have to use this instead of Hirsh's because the key is to keep it very thin and the tank must be glued back to a shell when done.So epoxy is necessary might as well use the same product throughout the repair. This is the tricky bit. You have to form a new glass shelf that provides enough surface area to get the strong bond needed. The fit must be very good, cast in place in fact so as to keep the bonding area free from spots that would get too thick and crack. You also have to be very careful to not use too much at the time of the bonding so that squeeze out does not form and provide another thick spot. A difficult process to be sure and it will be reserved for those that must save their tanks for originality purposes. We are going into a cost that will rival an aluminum tank being made. We are starting with a Fastback tank building one from scratch from a stock good old one first.The mold is made and is a work of art that those who have done this work would like to see. Resin that will hold this gas is only available in huge expensive quantities and is a false economy for these old bikes. So the new tanks will be lined because even the vinyl esters will fail but are better than the old way. We are a good ways off from even a testing of these principles so I will try to keep informed as to new info. Watching your efforts with interest though. Now if you really have some money we could make a stainless mold and cast the tanks in plastic. I have such a tank that is B-40 like and it will run 100% alcohol no problem. Cast from the same plastic that they make the bottles that you store it in.

You are really bursting my bubble :cry: When I redid my tank, I added a number of layers of cloth and epoxy resin so maybe doing so (as well as sealing it) will keep it sound for some time. I will nonetheless stay away from ethanol gas if at all possible.

Jean

Is 10% Ethanol gas bad for Fiberglass Tank

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