Plastic Tank problems: Discussion thread, see info thread sticky for updates

[DarkStaR]

Tank arrived, and will be installed on Saturday.

The service manager at the dealer I brought it to seems to knows about the problem, and asked me what I though, or what the rumor is.  I questionably answered with "the type of gas"... with out saying anything, he seemed to quietly agree.

[coarsegoldkid]

Is this tank expansion issue happening in all states.  Some states have different fuels.  I live in California and rarely see ethanol but will stay away from it if possible.

[Popeye the Sailor]

Is this tank expansion issue happening in all states.  Some states have different fuels.  I live in California and rarely see ethanol but will stay away from it if possible.

Where in California have you not seen ethanol?

[coarsegoldkid]

Maybe I haven't been paying attention to the fuel stickers on the pumps.  Maybe there aren't any stickers.  I always figured we didn't have it in our fuel.  So if ethanol is the culprit and it's in all fuel we are all screwed.    No need for steel tanks. Just having a plastic fuel tank doesn't mean plastic tanks are bad.  My BMW tank is plastic and has no issues.  BMW has been using them for years. By the way my friends 1100 Monster has a plastic tank with side covers similar to the BMW I think.  Are these newer tanks also prone to expanding?

[DUCURTI]

What coating?

I didn't have the extra $400 so I didn't get it and can't remember the name of it. I'll give the service manager a call and get back to you.

[CDawg]

I just discovered that I have the expanding tank problem too.  Rockwell has a new tank on order for me ($2,095) for my S4RS.  I'm on the fence about the coating too.

[lawbreaker]

... Looks like i'll be doing my SECOND warranty based tank swap. 

The replacement tank i have (replaced 2 yrs ago) is not only deforming on the sides but elongating too.... hitting the latch now.


I'm now in the market for a metal tank

[Bill in OKC]

NYLON 6/6 POLYAMIDE  (PA)
ZYTEL® 101F NC010 (Dry) (PA)
DuPont Engineering Polymers / Americas - Polymide 66
General-purpose nylon 6/6 has good toughness, tensile strength, and resistance to creep, particularly in
the high temperature range. Nylon has excellent wear properties. low coefficient of friction, and exceptional
chemical resistance to aromatic hydrocarbons, greases, and oils. Nylon is a hygroscopic material. Moisture
acts as a plasticizer reducing the tensile strength, stiffness, and increasing elongation, impact strength,
and energy absorbing characteristics. Outdoor weathering can be improved by the addition of carbon black.
Nylon will perform well in long range service in most applications at temperatures as high as 185°F (85°C).
Nylon is a translucent off white color.

This sounds like a match, alcohol absorbs water, nylon absorbs water, tanks expand...

[ducatiz]

NYLON 6/6 POLYAMIDE  (PA)
ZYTEL® 101F NC010 (Dry) (PA)
DuPont Engineering Polymers / Americas - Polymide 66
General-purpose nylon 6/6 has good toughness, tensile strength, and resistance to creep, particularly in
the high temperature range. Nylon has excellent wear properties. low coefficient of friction, and exceptional
chemical resistance to aromatic hydrocarbons, greases, and oils. Nylon is a hygroscopic material. Moisture
acts as a plasticizer reducing the tensile strength, stiffness, and increasing elongation, impact strength,
and energy absorbing characteristics. Outdoor weathering can be improved by the addition of carbon black.
Nylon will perform well in long range service in most applications at temperatures as high as 185°F (85°C).
Nylon is a translucent off white color.

This sounds like a match, alcohol absorbs water, nylon absorbs water, tanks expand...

damn

[Bill in OKC]

I wonder how much water e10 can contain before it becomes obvious.  Ethanol merchants must know.

[Howie]

I can't give you a good scientific answer like Bill (thank you) gave us on the properties of Polymide 66, but from my experience with gasahol in the late '70s and early'80s, a lot

[ducatiz]

I wonder how much water e10 can contain before it becomes obvious.  Ethanol merchants must know.

I have been talking with a lab that is going to examine a tank for me and I asked them this question a while back, I just got their reply in the last week.

E10 gasoline has been demonstrated to retain as much as 1% water (by volume), depending on the ambient temperature.  At a reference of 0 deg F, E10 has been shown to absorb 0.3% whereas at 90 deg F, the amount is as much as 1%.

This doesn't seem like much, but when it is compared to pure gasoline (G100), the percentage volume tops out at about 0.2% water absorption at 90 deg F.  Gasoline with MTBE show similar performance to G100.

I originally assumed the expansion issue was directly related to ethanol penetration, but after learning that PA6 / Nylon 66 has water absorption properties, I can hypothesize how ethanol is actually causing the problem.

Ethanol absorbs water, there is no way around it.

Phase separation is a phenomena which happens when Ethanol "enriched" gasoline sits.  Water present in the fuel mixture literally drags the ethanol out of the mix -- by gravity.  Water is heavier than gasoline and in solution it clings to the ethanol.

As a result, you end up with a pool of water at the bottom of your tank.

My recommendation for everyone is to store your bikes with an empty tank and to regularly use Stabil or similar solution to prevent phase separation.  Some are better than others -- "marine" formulations are just more potent.  Startron and Stabil have both indicated their products should have no problems in a nylon tank.

[duccarlos]

damn

+1

[Wonked]

Just got the call from BMW/Ducati of Atlanta - my tank's been approved. Should have it sometime next month.

Debating whether or not to do the Caswell coating, or the Stabil method mentioned above. Maybe both? $400 (Caswell coating parts and labor) seems a bit steep if the results are in doubt.

[ducatiz]

You can do the Caswell yourself for about 100 materials.

There are guys on the SC and Multis who did the Caswell over a year ago and still good.