Ducman62 Posted January 22, 2010 Posted January 22, 2010 I am the owner of a Moto Guzzi Tenni #105. Recently I've noticed the gas tank is starting to Swell and at the petcock area I am starting to see waves in the tank. Has anybody noticed the same on their tanks? The problem as I understand it the ethanol in the gas will cause this to happen. It know that DUCATI is replaceing their gas tanks under a 5 year deal for any of their tanks that have expanded into the steering damper and under some other circumstances. In the future they plan to make their tank out of metal. BMW had the same problem in 2002 and changed to metal. My Question does anybody know what Moto Guzzi is doing about their tanks that Swell or Deform.
ponti_33609 Posted January 22, 2010 Posted January 22, 2010 My Question does anybody know what Moto Guzzi is doing about their tanks that Swell or Deform. I have read in other posts I think here or at wildguzzi.com (by folks/dealers) that they are not doing anything if I remember correctly. Bob
DeBenGuzzi Posted January 22, 2010 Posted January 22, 2010 My original oo' sport tank is swelled, the fork tubes hit the tank just a hair before the steering lock and my new rosso tank isn't even CLOSE to that, on the plus side my old tank held at least a half gallon more of petrol so yes there is some merit to your worry but other than you I haven't heard of another with this problem and had started to think I was going crazy or just had a bad tank I also try to get straight gas as often as I can when I can find it at least its restricted in this state to classic cars and motorcycle, it also costs about .50-1.00 more per gallon to be ethanol and additive free
gstallons Posted January 22, 2010 Posted January 22, 2010 Maybe you could heat it up with a torch and push in on the part that is bulging out too far?
DeBenGuzzi Posted January 22, 2010 Posted January 22, 2010 Maybe you could heat it up with a torch and push in on the part that is bulging out too far? you can't be serious? how do you manage with a plastic tank, MAYBE a heat gun but direct flame sounds like a really bad idea, and the WHOLE tank is larger like someone inflated it, as in the term its slightly swelled at least in my case
raz Posted January 22, 2010 Posted January 22, 2010 I'm glad my Sporti has a steel tank. On the cog there's plenty of folks having problems with swollen Centauro tanks. No problem until you remove it, but if you do you may have a hard time getting it back on. Consensus now seem to be that if you have it off the bike for a while, it should absolutely not have fuel in it. I have no idea if that is a good advice but you can't go wrong following it. Unlike just about everyone else I don't think ethanol has anything to do with it. It's just a very convenient thing to blame these days.
gstallons Posted January 22, 2010 Posted January 22, 2010 you can't be serious? how do you manage with a plastic tank, MAYBE a heat gun but direct flame sounds like a really bad idea, and the WHOLE tank is larger like someone inflated it, as in the term its slightly swelled at least in my case I am joking ! I was checking to see if everyone was awake..............
emry Posted January 23, 2010 Posted January 23, 2010 We are seeing ethanol issues in some areas of the US. While the recommended maximum limit is 10%, our testing has found anywhere from 8% to 22% with an average of 12% across the US. 10% should not pose problems to modern vehicles, and is considered acceptable by all manufactures here (US) but older vehicles are experiencing problems with their plastics, fuel lines swell and slip off, floats distort, etc.. While my tank has not seemed to swell, I also have not had it off to really check.... It does not surprise me that our tanks may be susceptible.
dlaing Posted January 23, 2010 Posted January 23, 2010 One thing I have noticed is that if you take the tank off, leave it for a few days, it can stretch and you find yourself having a beotch of a time getting the bolt to line up. (but do NOT use a torch to soften it up) I need to get that tank suck problem back to counter the expansion problem, but higher capacity is a good thing, right?
luhbo Posted January 23, 2010 Posted January 23, 2010 As I understand this mechanism, the material itself is swelling. The molecular chains of the plastic are affected by the additives of the gas you have to use. If this process really should be reversible as Dave writes, then you could hope, try it out and then maybe insulate the inside with some special alcohol resistive coating. It's the same effect like oil greasing plastic bushings. They swell and render unusable. Hubert
mdude Posted January 25, 2010 Posted January 25, 2010 There was an article in the last issue of Classic Bikes about glass fibre aftermarket tanks for Royal Enfields. The ethanol additives in the fuel had apparently dissolved the inner coatings of the tanks and dumped it into the carburettors as a thick slimey goo.... nice... BUT: they didnt really know if it was the ethanol or just a bad batch of tanks.
Skeeve Posted January 25, 2010 Posted January 25, 2010 There was an article in the last issue of Classic Bikes about glass fibre aftermarket tanks for Royal Enfields. The ethanol additives in the fuel had apparently dissolved the inner coatings of the tanks and dumped it into the carburettors as a thick slimey goo.... nice... BUT: they didnt really know if it was the ethanol or just a bad batch of tanks. Combination. You can't use just any old resin for fuel tanks; as a for instance, standard polyester resin from the nearest hardware store uses acetone for clean up [acetone or other ketones being a component in modern "oxygenated" fuels.] Epoxy resins are more fuel proof, but require more exacting handling for proper layup. I suggest contacting Gudgeon Bros. for more info on what they'd recommend if you want to make your own fibreglas fuel receptacles...
emry Posted February 9, 2010 Posted February 9, 2010 While I may be prone to blame ethanol, I will not (but I have seen a wide variety of plastic/rubber problems that can attributed to it). My gas tank has swollen. While doing a battery cleanup (PC545, seems to vent gases just as bad as other sealed batteries [but mine is several years old, so this is not a comlpaint just an observation, but that is for another topic) I needed to remove my tank. It was very, very, very hard to do. It wouldn't clear the front tail section mounts. Reinstallation is not going to happen. The tank is approx 10-15mm longer than orginal (judged by firmly pushing forward and trying to line up the rear mount). Something is going on, and ethanol does match the profile. Be warned. Since I rarely ride anymore (I live across the street from work) I will let the tank "dry" and see what becomes of it. I will post a pic later. Clearly this info is for those of us that are stuck with 10% ethanol fuels.
DeBenGuzzi Posted February 9, 2010 Posted February 9, 2010 While I may be prone to blame ethanol, I will not (but I have seen a wide variety of plastic/rubber problems that can attributed to it). My gas tank has swollen. While doing a battery cleanup (PC545, seems to vent gases just as bad as other sealed batteries [but mine is several years old, so this is not a comlpaint just an observation, but that is for another topic) I needed to remove my tank. It was very, very, very hard to do. It wouldn't clear the front tail section mounts. Reinstallation is not going to happen. The tank is approx 10-15mm longer than orginal (judged by firmly pushing forward and trying to line up the rear mount). Something is going on, and ethanol does match the profile. Be warned. Since I rarely ride anymore (I live across the street from work) I will let the tank "dry" and see what becomes of it. I will post a pic later. Clearly this info is for those of us that are stuck with 10% ethanol fuels. yes this worries me, I'll have to try and go out of my way to get straight unadditive gas, its way more expensive and hard to find but as often as I can to slow the process on my new tank and my RSVR, I've heard ethanol be attributed to eating up a few RSVR fuel pumps, so I'm not thrilled I am virtually stuck with it.
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