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Fuel tank expansion due to ethanol


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1 hour ago, KINDOY2 said:

I think they are actually a type of Nylon from all I've read.

 

Lots of info if you search for problems with Ducati tanks. Because Ducs are far more plentiful...

including.... http://files.courthousenews.com/2010/11/19/Ducati.pdf

and....

"The tanks are made from Nylon 6/6, aka PA6 or Polyamide 6.  They are made by Acerbis." (Acerbis made our Guzzi tanks)

"Nylon 6/6 absorbs water.  Ethanol wicks moisture from the air and gravity causes the water to weigh down the ethanol so that it separates from the gasoline solution.  This means you end up with a pool of water at the bottom of your tank which is readily absorbed by the nylon surface."

https://onlinelibrary.wiley.com/doi/abs/10.1002/pola.1993.080310119

etc etc etc ....

If you need more convincing search Acerbis in the ADV world. Not really a concern there except for problems with paint and graphics not sticking.

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I had an expanded Ducati tank that I put out in our all glass " sun room" this summer..especially on those 100 deg plus days...it is unbearable hot.. I washed it with dish soap first then sat it on a

My experience is to run the tank down as low as possible before removing, and after removing just drain / pour out whatever fuel is left. I think it is better to let the tank sit empty. Also, a number

When planning for a tank-off on the V11, I run the fuel level as low as possible and prepare a place to set the tank (a saw horse works great to keep the pressure off the bottom of the tank which may

4 hours ago, KINDOY2 said:

I think they are actually a type of Nylon from all I've read.

 

And that isn't plastic? 

It's just not a consistent material.  And the fact they ran with it for years means they didnt give a crap about the gas.  It was all about the quality that they didn't care about. 

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Nylon is to plastic what apple is to fruit. So, yeah... it is specific type of plastic.

__Jason

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At its genesis, the issue is government forcing the sale of gasoline that is detrimental to the entire fuel system of cars, truck, motorcycles, lawn mowers, weedeaters et al.

Cleaner air is one thing. Add up the cost of the millions of cars, trucks etc. whose fuel systems have been damaged (thus emitting excess pollutants) then dismantled for repair, releasing gasoline fumes into the atmosphere. And the required chemicals necessary to clean the components and surrounding framework, etc. Those chemicals contribute to pollution. Then consider the mutiplicity of factories worldwide emitting smog into the air to make replacement parts and the chemicals to clean them. Intent versus impact should direct legislation. But it does not.

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3 hours ago, docc said:

After I dried out my tank (just letting it sit for maybe a couple weeks with the cap open at room temperature) I've had issues with spooge exiting the overflow/tank vent lines.  I've suspected that something changed with the internal lines that are "somewhat" coated in the tank's Nylon material. I say "somewhat" because I can see some big bulges along their lengths.

Not sure what changed, but it didn't spooge like this before I dried it out.

 

When this lockdown thing ends and life gets back to normal I'm going to see the guy around the corner thats a retired sheet metal craftsman that used to specialise in remaking and repairing bodywork for exotic cars and classic restorations. I'm going to ask him to teach me this art form if he will. I thought a good thing to learn on would be a V11 sport alloy tank. I'd like to actually make all the formers and bucks so I could make quite a few.....dreams,dreams.

Ciao    

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3 hours ago, LowRyter said:

And that isn't plastic? 

It's just not a consistent material.  And the fact the ran with it for years means they didnt give a crap about the gas.  It was all about the quality that they didn't care about. 

Yeah I'd call it plastic. They're reasoning I'd guess was more about politics maybe. Ethanol in fuel, in the US at least, has been a hot potato for some time. The Italians maybe took the world view. ?

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1 hour ago, Lucky Phil said:

When this lockdown thing ends and life gets back to normal I'm going to see the guy around the corner thats a retired sheet metal craftsman that used to specialise in remaking and repairing bodywork for exotic cars and classic restorations. I'm going to ask him to teach me this art form if he will. I thought a good thing to learn on would be a V11 sport alloy tank. I'd like to actually make all the formers and bucks so I could make quite a few.....dreams,dreams.

Ciao    

I've been hounding my local panel beater, a very talented friend, for several years to make me a tank. He is so covered up he has given up his well paying job in the medical field and still has no time for me.

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16 minutes ago, footgoose said:

Yeah I'd call it plastic. They're reasoning I'd guess was more about politics maybe. Ethanol in fuel, in the US at least, has been a hot potato for some time. The Italians maybe took the world view. ?

I guess my point is am skeptical that it's caused by fuel but just poor quality control due to it being molded plastic.

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13 minutes ago, LowRyter said:

I guess my point is am skeptical that it's caused by fuel but just poor quality control due to it being molded plastic.

It's the fuel. Non of my bikes are run on Ethanol fuel and non have tank swelling issues.

Ciao

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The distortion is certainly caused by the alcohol in the gas. I'm simply making the point that the US market having ethanol fuel was not a financial consideration.  So yeah, a quality control issue.

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52 minutes ago, LowRyter said:

I guess my point is am skeptical that it's caused by fuel but just poor quality control due to it being molded plastic.

Plastic contains chemicals which, by class, are known as plasticizers. They lend the flexibility and resilience to the base material. With heat and time, these plasticizers migrate out, through oxidation, heat cycles, sunlight (UV) or exosure to other chemicals and solvents. Thus old plastic of virtually all types becomes brittle. It usually shrinks, as its component parts leech out. But Guzzi tanks expand. That is from the chemical content of the gasoline  which they store. Ever clean rubber parts with alcohol? Some types will blow up like a balloon. Add that alcohol to gasoline and you get the same result.

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39 minutes ago, po18guy said:

Plastic contains chemicals which, by class, are known as plasticizers. They lend the flexibility and resilience to the base material. With heat and time, these plasticizers migrate out, through oxidation, heat cycles, sunlight (UV) or exosure to other chemicals and solvents. Thus old plastic of virtually all types becomes brittle. It usually shrinks, as its component parts leech out. But Guzzi tanks expand. That is from the chemical content of the gasoline  which they store. Ever clean rubber parts with alcohol? Some types will blow up like a balloon. Add that alcohol to gasoline and you get the same result.

Its been well recognised for years that the issue with the tanks swelling isn't the Ethanol but the additional water content held in suspension it attracts. This isn't a mystery that needs to be raked over again.

If you run non Ethanol fuel you never have an issue. No ethanol, no significant water content in the fuel and no swelling problems. 

Ciao

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Am wondering how a tank kept full or near full and with a closed cap would attract the massive amount of water to grow the entire tank. Must be an SAE paper on this somewhere. From the source below I read the following:

Nylon 6, produced via the ring-opening reaction of the compound caprolactam is structurally similar to nylon 66 and has similar properties and uses. It is widely used in Europe in place of nylon 66, but not in the United States. (See Figure 5.)

Nylon 6,10 and nylon 6,12 are also commercially available. Because of the presence of the additional methylene (–CH 2 –) groups that are hydrophobic (water-hating), these nylons are more resistant to moisture and more ductile than nylon 66.

 
This document shows that nylon (if that is the polymer used in the tanks) has high resistance to both water and ethanol. Other alcohols have a deleterious effect. So, is it a chemical used in the US refining process or additive package which causes the anomaly?
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10 minutes ago, po18guy said:

Am wondering how a tank kept full or near full and with a closed cap would attract the massive amount of water to grow the entire tank. Must be an SAE paper on this somewhere. From the source below I read the following:

Nylon 6, produced via the ring-opening reaction of the compound caprolactam is structurally similar to nylon 66 and has similar properties and uses. It is widely used in Europe in place of nylon 66, but not in the United States. (See Figure 5.)

Nylon 6,10 and nylon 6,12 are also commercially available. Because of the presence of the additional methylene (–CH 2 –) groups that are hydrophobic (water-hating), these nylons are more resistant to moisture and more ductile than nylon 66.

Well define massive amount of water. What makes you believe the suspended water enters your fuel after it's in your tank? I dont recall the fuel I buy being delivered to the gas station in hermetically sealed trucks and stored in air tight storage tanks. The anecdotal evidence also suggests owners living in more humid environments also suffer the problem to a greater extent. 

Ciao 

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