Fixing SWOLLEN TANKS!

[Phil/TX]

Wow the tank just would not quite fit, I needed 1/4 inch to get the mount bolt in. So I put the thinking cap on  
I had used a ratchet strap to pull kick stand springs on before, so why not try one on the tank, I took precautions not to scratch the tank. And what do you know, it worked.

[moto-uno]

  I'm not familiar with those tanks BUT , is that how they are supposed to look ?   Peter

[guzzisteve]

I have fixed a bunch. If you have the tank off, take the front rubbers off the frame. Now you can slice off enough rubber for it to slide up in the tank farther. 1/4 " is pretty normal. It happens on V7 Classic tanks too.

[Muzz]

Blame the alcohol in your fuel, that's the usual one swelling plastic tanks.

[Stevex]

Ethanol absorbs moisture resulting in water in the tank.
Nylon tank absorbs water and expands.

[moto]

Ethanol absorbs moisture resulting in water in the tank.
Nylon tank absorbs water and expands.

Agreed.

Will tanks shrink back to their original sizes if the use of ethanol is discontinued?

[Mayor_of_BBQ]

Agreed.

Will tanks shrink back to their original sizes if the use of ethanol is discontinued?

I doubt it because the ethanol-free gas is hydrophobic...  Mine shrunk back to fit only after I drained it completely and removed the gas cap and fuel pump bung and let it completely air dry out for several weeks (not sure if it takes that long, thats just how long mine was empty

[lucky phil]

Ethanol absorbs moisture resulting in water in the tank.
Nylon tank absorbs water and expands.

Yes thats it. If you drain the tank and dry it out for a few weeks they tend to come back to near normal. Personally I'd drain the tank and set up a air re-circulation system to run through it for a few days and see what happens.

Ciao

[moto]

I just googled-up a Ducati owner's report of success in shrinking his tank in a matter of four days by using aviation unleaded race gas.* He believed the response was faster than would be achieved by airing out the tank.

https://www.ducati.ms/threads/will-ethanol-expanded-plastic-tanks-shrink-back.99530/

I don't see any reason why the usual (around here, at least) alcohol-free gas wouldn't work too. My understanding of plastics (after my deep-dive into dashboard sealing possibilities) is that they will reach an equilibrium with the environment in terms of the moisture being held inside them, some faster than others.

Of course if there is no alcohol-free gas available for regular use this plan of action is not much help. But if the OP can switch to non-ethanol gas it would seem worth trying.

My Griso has almost never touched the hard stuff and shows no problem, by the way.

Moto

*EDIT: "VP's C10 race gas is an unleaded 96 octane non-oxygenated (no ethanol) race gas."

[moto]

Just an afterthought. The Ducati owner reported a striking success, such a success that anyone should be able to replicate his experiment using alcohol-free auto gas. If I were doing this I would run the ethanol gas out of the tank, fill it up with ethanol-free, and then remove the tank from the bike and place it on the work bench for several days.

Once on the bench I would lightly mark reference points on the sides and front and rear of the tank and then use a try square (or a plumb bob) to mark the bench (or a piece of paper on the bench) showing the width and length of the tank at exactly those points.

Such an experiment would be a great boon to others, if done well.

Moto

[TN Mark]

Blame the alcohol in your fuel, that's the usual one swelling plastic tanks.

Or blame Piaggio for not specifying the tank be supplied made from materials that  don’t distort due to Ethanol. Burning food for fuel is a silly idea from the outset, but here we are. Other manufacturers of all sorts of products seem to be able to cope with reality and it’s well past time for Piaggio to do the same.

[Bisbonian]

Or blame Piaggio for not specifying the tank be supplied made from materials that  don’t distort due to Ethanol. Burning food for fuel is a silly idea from the outset, but here we are. Other manufacturers of all sorts of products seem to be able to cope with reality and it’s well past time for Piaggio to do the same.

Seriously, ethanol has been used in gas in the US since the 80s (at least). If a manufacturer hasn't figured out a better way to deal with it over the past 40 years then it's not the fault of the fuel.

[john fish]

Ducati tanks are affected and so is the tank on my MZ.  Fwiw, draining the tank on my MZ and letting it sit empty all winter long did not help.

[Mayor_of_BBQ]

Or blame Piaggio for not specifying the tank be supplied made from materials that  don’t distort due to Ethanol. Burning food for fuel is a silly idea from the outset, but here we are. Other manufacturers of all sorts of products seem to be able to cope with reality and it’s well past time for Piaggio to do the same.

To be fair, none of the bikes this seems to be an issue with have been produced in the last 5-10years.. and at least in Guzzi's case, the tanks come from Acerbis- who make like every aftermarket dirtbike/DS tank in the world.  I don't know if the Ducati tanks are cut from the same cloth (nylon).. didnt Triumph have this problem with Tiger tanks as well (peeling/bubbling claw mark decals)?

[MGrego]

Wow the tank just would not quite fit, I needed 1/4 inch to get the mount bolt in. So I put the thinking cap on  
I had used a ratchet strap to pull kick stand springs on before, so why not try one on the tank, I took precautions not to scratch the tank. And what do you know, it worked.

Yep, same experience with my Norge tank.  I used a little scissor jack and a 2x4 between the tank and the frame to "push" the tank up to where the bolt lined up.  Your method looks like it worked well too....

[blackcat]

My 07 Norge tank swelled up years ago and it hasn’t had the bolt in place for the last 5 plus years.  Oh well.

[Jim Rich]

Good job Phil!

[Motormike]

PA-6 nylon roto-molded tanks made by Acerbis of Italy.  Virtually every manufacture in Europe used them on street bikes for a while in the early 2000's, Ducati, Triumph, Moto Guzzi, etc. all with the same result when exposed to ethanol gasoline.  The sad thing is, even now, BMW and Ducati still use a type of plastic fuel tank (fuel cell?) on models like the BMW R1200gs and the Ducati Multistrada 1200.  The newer type of plastic won't hold pant, so the manufacturer covers it with shiny plastic panels..that then are pushed out of alignment when the fuel tank expands! 

[lucky phil]

My 07 Norge tank swelled up years ago and it hasn’t had the bolt in place for the last 5 plus years.  Oh well.

I had  DB1 Bimota with a plastic tank under that one piece bodywork that swelled up so bad the bodywork had to be levered back on. I recognised that if this was the way it was going to be the bodywork would eventually get stress fractures. My solution? I had commissioned a custom made alloy tank by a chap that made exact replicas of C and D type jags complete with full aluminium chassis and body work. Problem solved, at a price

Ciao

[LowRyter]

Sure, it's the ethanol.  Nothing wrong with those tanks. 

[Motormike]

Sure, it's the ethanol.  Nothing wrong with those tanks.

Amazing how many Ducati Multistrada owners I've met that say "nothing wrong with my tank," until I pull up next to them with my exact same model that has never seen E10 gas and begin to point out the areas of swelling on their bike...here...here. ..here, etc.  Their smile changes to a frown real quick. 

[tris]

I have fixed a bunch. If you have the tank off, take the front rubbers off the frame. Now you can slice off enough rubber for it to slide up in the tank farther. 1/4 " is pretty normal. It happens on V7 Classic tanks too.

I found on my B1100 that a good coat of lube on the rubbers helped too

[lucky phil]

I found on my B1100 that a good coat of lube on the rubbers helped too

Yes lubing the rubber mounts on just about any tank makes life a whole lot easier.

Ciao