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Saturday, June 14, 2014

Aprilia Gas Tank

The last time I worked on my Aprilia, I may have gone on a nice little rant about ethanol fuel. Ethanol fuels cause certain types of plastic and composite fuel tanks to swell. It's a little irritating when you go to put a tank back on a bike and it is longer than it is supposed to be and won't fit back on. The solution? Well, I got a used tank to run on the bike until my original one dries out and shrink back down.

With the two front mount bolts removed, the tank will pivot up. The two lines in the upper left are vents, simply disconnect them. The upper right hand line is the return. When you pull that line, if there is any gas in the tank, it will come out there. The banjo close to the center is the pressure line from the pump. A little gas will come out of there, but not a lot. The leads coming out of the bottom right go back behind the batter. They have a connector back there that simply unplugs.

With the vents, return, and electrical disconnected I flipped the tank and laid it on a chair. This made it easier to break the banjo fitting.

At the work bench. There was a little fuel remaining, I used the blue line to drain it into a gas can. When that Was done, the plate and the the two vent fitting in the lower left can be removed.

This is the pump unit.

While we're here, we're going to replace that little piece of tubing. It has a tendency to fail.

Fuel hose improvement kit. $20 of cheap insurance.

Installed. The pump unit is now ready to transfer to the new tank.

I moved the cap to the new tank. It's a temporary tank, so I'm not worried about the peeling clear coat.

Pump unit transferred. Ready to go onto the bike.
All lines reconnected.

While I had the tank off, I changed the front mounts to quick disconnect pins.

It doesn't match, but it will do. Now, just add the oil back in (took out the oil when I did the stator) and add gas. This leaves (hopefully) only one task left on the bike. The swing arm is going to get replaced. The existing one isn't in danger of killing me at the moment, so I will do it when I have time.
 How do I prevent this from happening again? There are two ways. Get the boneheads to get rid of the ethanol mandate (ha! like that will ever happen) or add a sealer to the tank. When my tank is back to the right size, I will go through the sealing process.


  1. That sure is helpful! It can be difficult to work on the Aprilia's gas tank manually, though your method explained how it can be done easily, without fuss, in a clear and elaborate way. Thank you for giving us the rundown, Mark! I just hope they'll add a sealer to the tank. All the best to you!

    Abraham Yates @ Apache Oil Company

    1. It has its tricky moments. I'm used to a different sort of bike, with less complicated fuel system. I should see if the original tank has shrunk back down yet. It's been almost a year.