Wildguzzi.com
General Category => General Discussion => Topic started by: nwguy on June 25, 2021, 05:40:12 PM
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Went to put my gas tank back on after changing inner plugs and alternator belt. The rear mounting hole is out of alignment with the threaded mounting hole in the frame by almost 1/4", so I can't reinstall the tank. I removed the tank, cleaned the 2 recesses at the front with denatured alcohol and paper towels, then silicone sprayed the tank recesses. Wiggled the tank on as before, and same result. I had this happen with an 05' Multistrada and ended up with 2 tanks, one dries while the other is in use. I hate to think this is happening again. Admittedly it's hot here in the NW now, but the tank's been in my shady garage for weeks now. I've thought about trimming the 2 rubber mounts at the front to allow the tank to slide forward. Or, I could mill out the hole in the frame plate so it's slotted, and then use a washer and nut with the tank's bolt. Don't know if the seat would still fit OK then. Any thoughts?
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Ethanol gas strikes again! If you had a first-gen. Multistrada you should be familiar with the problem. Both bikes have a plastic fuel tank made from PA6 nylon, which expands when exposed to ethanol laced fuels.
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I have cut many rubber tank bumpers. The tank grows but doesn't get smaller that I've seen. I have two 3/4" wood for this. Set up like a tent between back of tank mount to where the fuses are in back to the flat spot. Push down on the peak and tank goes forward and it's easy.
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I have cut many rubber tank bumpers. The tank grows but doesn't get smaller that I've seen. I have two 3/4" wood for this. Set up like a tent between back of tank mount to where the fuses are in back to the flat spot. Push down on the peak and tank goes forward and it's easy.
I tried jacking the tank back with bits of plywood and 2x2s. Could make it go about 1/8", but that's it. Fraid I'll have to sand the bumpers.
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Had the same problem. First time I used ratchet straps, wood, etc and forced it to fit. A year later a small piece of my upper fairing broke off... seems related. Anyway - this year i removed the tank and drained it in December. April 1st I tested the fit and the tank fit perfectly. I then coated the inside of the tank with the product from caswell. So far so good.
Eric
EDIT - I also removed the he plumbing and vented the tank as per the "rest of the world"
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There is a fuel tank pressure relief valve you might sometimes hear (screeching) on a hot day, as pressure from gasoline fumes builds in the fuel tank.
Until I removed this valve, and vented to atmosphere, ala the 'rest of the world' (Euro, top photo) standard, my 2008 1200 Sport fuel tank developed nasty little bubbles that ran above the plastic/chrome wings on the fuel tank. Once I removed the pressure relief valve and plumbed the system using the European layout, no more bubbles/bumps in the fuel tank. Matter of fact, they went away on their own. Did the same on my 2012 Griso, after I'd replaced the fuel tank under warranty due to deformation issues. See PN 7 on second drawing.
Even after doing this, I usually had to insert a large Phillips screwdriver in the fuel tank rear mount and the fitting that held it to the bike, and lightly push it toward the front to get the tank mount holes to align, permitting me to bolt the tank back to the bike.
YMMV!
(https://i.ibb.co/rtS2J7h/Slide1.jpg) (https://ibb.co/rtS2J7h)
(https://i.ibb.co/gF4zgcc/Slide2.jpg) (https://ibb.co/gF4zgcc)
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What the others said.
And, yes, maddening. :cry:
I have two tanks for my Norge.
Most years -- code for "lethargy & sloth" :rolleyes: -- I swap them. Rinse the "old," and let it sit until next year. Works.
Bill
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What the others said.
And, yes, maddening. :cry:
I have two tanks for my Norge.
Most years -- code for "lethargy & sloth" :rolleyes: -- I swap them. Rinse the "old," and let it sit until next year. Works.
Bill
This is exactly what I did with my Multistrada. Crazy. I sold it because of that and the valve adjustment requirements. Loved it other than that.
Here's the bit I trimmed off the rubber mounts. Fits now, though tightly.
(https://i.ibb.co/qJLRfHK/IMG-20210625-190648951-1.jpg) (https://ibb.co/qJLRfHK)
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If you still have the evap canister pictured in the diagram, eliminate it.
Plenty of how-to explanations if you search...
Best single mod for the Norge besides swapping out the oil temp sensor.
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I have heard of Guzzi's from the early part of the 2000's having this problem (and many other brands with plastic tanks) - I have had (and do have) several Guzzi's from V11 Sports to a Stelvio and have never had the issue. I do run high test E-Free fuel every few tanks, and will periodically simply siphon the ethanol fuel from my Guzzi's if I am not going to ride them for a while, and leave them sit with the filler caps open.
Perhaps 2 years ago, I called MG's main US office in New York and was able to speak with a rep there. She said that there just happened to be an engineer from the factory whom she would speak with and call me back. She did call me back later that day and stated that the engineer said E fuel is fine to run as long as it is over 90 octane, but not to leave the bike stored for long periods (perhaps months) with ethanol fuel in the tank. So, at least Guzzi had a comment for this issue, and since I have always stored my bikes with low/no fuel left in the tanks, I fortunately have avoided the issue.
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My 07 Norge tank started expanding years ago but up to about 5 years ago I could persuade the rear bolt into place but that is no longer the case. I just gave up and ran a zip tie through the hole of the tank and the bolt hole once it was completely impossible to install the bolt. And I have a brand new spare tank but this seems to be working OK.
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There has been a running debate about if leaving the fuel tank empty to "air out" will cause it to shrink back to (or at least closer) it's normal shape. Some say yes, others say it doesn't help. As the owner of not one, but two Ducatis with the dreaded plastic fuel tanks, I've read and studied the problem for years. All the tanks in question, as far as I know, are made and supplied by Acerbis of Italy for Ducati, Moto Guzzi, etc. The tanks are roto-molded from PA-6 nylon, a white plastic which the manufactures loved because it held paint well, and could be molded into almost any shape. Unfortunately, PA6 nylon is hygroscopic, meaning it will absorb moisture. One engineering report I read said PA6 nylon can absorb up to 10% of its weight in water. This is actually what causes the expansion, rather than a chemical reaction to the Ethanol directly. It's also why some say leaving the tank open in a dry environment will allow it to shrink back towards its normal shape as (if?) the moisture escapes.