Ducati GT 1000 Loose Fuel Tank Problem

Edtior's Note: This is an update "GT1000 Fuel Tank Problem?" posting from my Ducati GT1000 blog

See also the Ducati GT1000 Fuel Line Recall article for more information | Removing the GT1000 Fuel Tank

Background
We received a few emails recently from GT1000 owners who were asking if we knew anything about a problem with loose GT1000 fuel tanks.

Apparently, some owners have been experiencing a "spreading" problem, where the polycarbonate (or so I'm told) fuel tank starts to spread or sag and the front fuel tank holders no longer do their job. The fuel tank becomes loose in front, a potentially dangerous problem.

I hadn't experienced this on my bike, until very recently, when I pulled the tank to install a relay wiring harness for an upcoming horn article Burn and I are working on.

Here's a copy of an email that describes the problem, repeated from the GT1000 Blog entry that was sent by webBikeWorld visitor J.D., :

"I don't know if you're hip to this, but the SportClassic polycarbonate fuel tanks, especially the GT1000 tanks, have been prone to "spreading" and hence not connecting with their front mounting pegs.

The result is that the front mounts for the tank don't work and the front of the tank is loose. This puts undue stress on the single bolt that holds the back of the tank. This is a warranty fix. Ducati knows about it and is replacing a lot of tanks, mine included.

Check your tank. If you can grasp it at the lower front and pull it out of the "pegs", then you should get a replacement tank. I asked my service guy if the new tanks were any better and he said that they would probably warp in the same way since they are made by the same manufacturer and of the same material.

So...? Pro Italia said that they were going to make longer "pegs" or whatever one calls them so that the tanks would be more secure to the frame as a fix. But, right now, I'm getting a new tank at Ducati's expense."

It's hard to believe that something as simple as a fuel tank attachment would or could be a problem, but there you have it. I discovered it once I loosened the single bolt at the back of the tank (see this article on removing the GT1000 fuel tank), and realized that the entire tank could be lifted straight up and off the bike with nothing to catch it.

This isn't how it's supposed to work; there are two U-shaped brackets that are (fortunately) bolted on either side of the bike, attached to the top frame tube. Two matching rubber bumpers underneath the fuel tank are supposed to slip into these U-shaped brackets and hold the tank in front.

The system worked when I first got the bike, but apparently, the spreading problem is real -- the fuel tank has spread out at the bottom, possibly due either to insufficient internal support or -- I hope not -- fuel softening the polycarbonate?

In any case, there's an easy fix. Whether or not this is a permanent fix is yet to be determined. If the fuel tank doesn't deflate any farther, I'll be OK. I'm going to check with the dealer on this, although at least one webBikeWorld reader told us that the dealer he talked to would replace his tank, but he would expect the same problem to happen again, as the replacement tanks are made from the same material by the same supplier.

Disclaimer
We don't usually post disclaimers because we assume webBikeWorlders are the most intelligent, knowledgeable and safest motorcycle owners and riders on the planet. True, right??

But note that messing with the fuel tank is a serious and potentially dangerous project. All of the fuel should be safely drained from the tank prior to starting this project. The battery should be disconnected -- although on the GT1000, the fuel tank has to be lifted first to get to the battery.

This job should be done outdoors, away from the garage or house. Also, I don't know if this "solution" is recommended, or if it's dangerous, or will cause other problems. I'm only reporting what Burn and I did and it seems to work so far -- I don't know if it will work for you or if it will permanently solve the problem.

The Fix
It's simple: Add a few 6 mm washers under the U-shaped bracket that holds the rubber bumpers. I went down to the hardware store and got some M6x25 SHCS (socket head cap screws) and some 6 mm washers. I had to experiment to see how many washers it would take; I started with 2, which helped but the tank was still slightly loose, so I went to 3 on each side and the tank is now tight as a drum.

In fact, I had to give it some muscle to get the rubber bumpers to push up into the brackets. As long as the tank doesn't spread any farther, I'm all set.

By the way -- I first tried using a pair of Channelock pliers to spread the U-shaped brackets out, but that actually made the problem worse, because when they're spread out on the bottom, they push in at the top, and there's nothing left to prevent the rubber bumper from slipping right out the top.

Here it is in photos; again, read my article on removing the GT1000 fuel tank first:

Ducati GT1000 Fuel Tank Bracket

In the photo above, the fuel tank bolt in the rear has been removed and the fuel tank is lifted. The bracket in the center of the photo is the culprit. After the fuel tank spreads, the lips of this bracket are too short to hold the rubber bumper that can't be seen up underneath the fuel tank.

Remove the two 5 mm SHCS and remove the bracket. The nuts that hold the screws are permanently attached to a bracket welded to the frame tube, so all you have to do is back out the screws.

In this photo, the stock silver-colored 6 mm SHCS is in the center of the three. The 25 mm long SHCS is at the right with 4 washers. Note that the length of thread after the 6 mm flat washers have been placed on the screw is about the same as the amount of thread length of the stock silver screw.

Close-up of Ducati GT1000 Fuel Tank Bracket Fix

Here's a close-up of the U-shaped bracket with the new M6x25 SHCS and the three 6 mm washers. Remember that the washers have to go on the side shown so that the bracket will stand out from the frame by that amount, in effect making the U-shaped bracket wider.

Ducati GT1000 Fuel Tank Spreading Problem Fix

Here's the finished product. The U-shaped bracket is installed with the 3 washers. Note that the bracket is now standing out from the frame by the width of the washers.

You may want to use some blue Loctite on the threads to make sure the screws stay put.

Be careful when re-installing the fuel tank. Put your hands underneath and feel to make sure the rubber bumpers under the tank are sliding correctly into the U-shaped brackets on either side.

Note that you may need more or less washers, but I wouldn't go more than 4 wide.

Please send comments or any tips you might have on this project to the email address below.

Posted Date: July 31, 2008.

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