So, this winter I did the 18K mile service on my Monster which included replacing the fuel filter. This is located inside the gas tank and requires the removal of the filler cap. All went well with replacing the filter (and the service), but in the process the "rubber" line for the gas tank vent was torn, causing a unpleasant trip to the gas station where I stood and watch my bike pee about a gallon of gas all over the place. The factory service manual was very explicit about not disconnecting the lines to the overflow and the vent from the cap when changing the fuel filter, but I cannot see why and in retrospect this is what caused the line to tear. Probably a time savings for the Ducati mechanic. Oh well, live and learn.
I posted that saga in the Tech section here:
Gas flowing from vent spigot on gas tankI had to replace the line and bought tygon gas line from my local autoparts store. I am happy to report that the repair was a success and that all of the gas stayed in the tank at the station (and then was burned in a celebratory ride through the rolling hills of southwestern Wisconsin).
These pictures are of removing the gas tank filler cap to replace the broken vent line. Enjoy!
This is the gas cap.
![](http://farm5.static.flickr.com/4045/4467460675_bee79ec343_b.jpg)
Gas cap open (sorry about the IZ_ picture).
![](http://farm5.static.flickr.com/4028/4468237616_4600fd8790_b.jpg)
Gas cap removed from base (note the three of the five bolts that need to be removed and the "safety" bolt under the cap). The depression is for the gas tank overfill drain and the hole with the rubber nub is for the vent line.
![](http://farm5.static.flickr.com/4053/4467463899_0fb2ae775d_b.jpg)
Cover the openings to prevent screws and debris to go inside the tank. I used painter's tape.
![](http://farm3.static.flickr.com/2736/4468239728_c61978f5ec_b.jpg)
Remove the 8 grub screws from around the gas cap base in order to remove the base. You should do this in cross pattern like with an auto wheel. I also use tape to mark the position of the cap base in relation to the tank (so my cap is "straight").
![](http://farm5.static.flickr.com/4055/4468240834_b9a7c23bf7_b.jpg)
Pop out the base. Note the broken vent line.
![](http://farm3.static.flickr.com/2801/4468242062_9b69dc6d9d_b.jpg)
A shot inside the tank. The metal nipple with the hose clamp is where the vent line should be connected to. On the gas cap base there is a green o-ring that needs to be greased when the base is placed back on the tank and the the black o-ring needs to be removed to fit on the tank (at least that is how I do it).
![](http://farm3.static.flickr.com/2797/4468243282_2faf4c4cb9_b.jpg)
New line fitted.
![](http://farm3.static.flickr.com/2695/4467469847_3c551d039d_b.jpg)
Connect to the fuel cap base.
![](http://farm5.static.flickr.com/4045/4468245774_16c202f913_b.jpg)
Grease the green o-ring and set the base back on to the gas tank. Line up the tape marks. The black o-ring that seals the top of the base to the tank has been removed from the base. Do not push down yet!
![](http://farm5.static.flickr.com/4007/4468246868_d06247f6a9_b.jpg)
This is the black o-ring that can be difficult to replace.
![](http://farm3.static.flickr.com/2786/4467473433_28b95c2c51_b.jpg)
Now push down lightly on one side of the base. Slip the black o-ring in at that point and push down harder on that spot to seal the o-ring to the tank. Continue this around the base. Stretch the o-ring over the base. It might feel like it is going to tear, but mine is the original o-ring and it has been out over a half dozen times.
![](http://farm5.static.flickr.com/4046/4468249180_6001f452ae_b.jpg)
Now hold the o-ring and push down on last part of the base. Release the o-ring and push! Now the o-ring should be in place. Push down on the base with even pressure. Check the fuel line for kinks and that they are still connected. Refit the 8 grub screws, gas cap, 1 safety bolt and the 3 gas cap bolts. You're done, now go for ride!
![](http://farm3.static.flickr.com/2747/4468251556_7e5fcce2b8_b.jpg)