SUBJECT : How to change a fuel filter

BIKE: 1998 Ducati ST2

DATE: 7/13/2003

AUTHOR: George Berkhofer

Time Required: 3-4 hrs

Tools Required:

13mm Socket (Deep socket better)

7mm Socket with universal joint

5mm Hex Key

3mm Hex Key

Blade screwdriver

Philips #2 or #3 screwdriver

Funnel

Gas Can

Supplies Needed:

Fuel Filter &endash; Ducati Part #425.4.004.1B $24

O-Ring &endash; Ducati Part # 886.5.001.1A $12

Optional Supplies

~3 ft. Fuel Line Hose from Auto Parts Store

Notes:

This projects requires handling of a gasoline, and as such, safety measures such as working in a well-ventilated environment, not smoking, and removing items that may cause sparks are all advised. This may also include disconnecting the battery. Also, if you are able to, it is best to try and have as close to an empty tank as possible to minimize the amount of fuel you must handle.

Procedure

On a cool bike, parked on center-stand, remove the two button-head bolts securing the key cover on the top of the fuel tank. Set cover aside, and save bolts, they will be used later.

Remove the seat

Un-hook front clip holding the tank down.

Lift tank upward, rotating on rear pin, and place prop-rod in place to secure tank in upright position. (If possible, you may want to find a longer prop to put the tank at a higher angle. This allows the fuel pump to be a bit more accessible. I used a long piece of rod iron, and propped the tank up by its rubber side bumpers.)

Pad the area directly under the fuel pump very well with paper shop towels or other very absorbent materials, as gas will likely drip.

Disconnect the electrical connector going to the fuel pump.

There are two fuel lines going to the fuel pump. One is marked with a white collar that has the letter R on it, the other has a M. Take note of which is which. The R line goes in the middle stem, and the M connects to the stem that is closest to the outside edge of the tank.

One at a time, loosen the hose clamps on the lines, and remove them from their stems. Some fuel will spill. It will stop however; have plenty of paper-towels close on hand. (The hose clamps should be 7mm) Also remove the small gas overflow tube that is attached to the fuel pump.

Remove the rear latch that the tank rotates on, and lift the tank off of the bike.

Lean the tank forward so as to move the gas forward, and remove the drain plug at the very rear of the tank with a 5mm Hex Key.

Carefully lift tank, and allow fuel to drain into gas can with a funnel. Wait and make sure all gas is emptied.

Replace the drain plug.

On a soft surface, (if you are careful, you can re-attach the tank to the bike and lean it all the way backward. I had a couple motorcycle tires that worked perfectly as a base) remove the three 13mm nuts around the edge of the fuel pump.

(For this step, you need three bolts. I am not sure the exact size/pitch of the bolts, but the bolts from the key cover work, thus you already have two, you only need to find one more bolt that is the same size.) Thread the three bolts you have gathered into the threaded holes around the edge of the fuel pump until they reach the bottom of the tank. Working a small bit at a time, slowly screw in the bolts, working them evenly around the circle as to evenly raise up the fuel pump, until the pump is free.

Slowly lift the fuel pump. You may have to reach inside to work some fuel lines over the edge of the hole. You will not be able to lift it a great deal, as there are lines attached to it.

There are two vent lines that run from the ceiling of the tank to the fuel pump. These are connect to the fuel pump at two places around the edge. Unscrew the hose clamps on the vent lines and pull the lines free of the pump.

You will now be able to pull the pump out a bit more. There is an electrical connection inside the tank that connects the fuel pump to the fuel level sensor. Disconnect this connection.

Working the lines inward to clear the opening, work the fuel pump outward until it is completely free of the tank.

There is fuel in both the fuel pump and fuel filter. Thus, for the following steps, make sure you are working in a spot that can have fuel leaked on it, or at least over a catch pan.

The fuel filter is the metal can that above the fuel pump. Remove the new filter that you have purchased, and compare the two side to side while the old one is in place. Take not of the arrow on the filters that show the direction of flow to ensure you orient the new filter correctly.

Remove the two Philips screws securing the top and bottom hoses to the filter.

Loosen the 3mm hex bolt that secures the plastic band holding the old filter in place, and remove the old filter. Fuel will spill from old filter.

Fit the new filter in place making sure that the orientation is correct. The flow arrow should be pointing toward the fuel pump. Secure the plastic band and refit the two hoses at the top and bottom of the filter.

Remove the old, green O-Ring at the base of the fuel pump. The new O-Ring should be a snug enough fit to hold it in place.

In the tank, inspect the two vent lines for damage. (At 16,000miles, my vent lines were very deteriorated and flaking badly. This can possible enter the fuel system and clog the filter prematurely.) If you are replacing the vent lines, follow below. If not, skip to step 29.

Replace all fuel lines with the correct size and part from Ducati. Don't mess around trying to find similar lines from an auto parts store. This is one area you do not want to cut corners.

Using a ?" socket wrench, universal joint, and possibly an extension, reach inside the tank; remove the old hose clamps and hoses. Lay the old hose next to the new, and cut the new hose to fit.

Attach the new hose with hose clamps to the top of the tank and allow to dangle out of the bottom for re-attachment.

VERY IMPORTANT, using a grease, or Vaseline, lubricate the inside lip of the fuel pump hole where the O-Ring will contact the side making a seal. If you do not lubricate this, re-installing the pump is near impossible, just trust me on this one!

There is a mark on the bottom of the fuel pump that reads "Front". Make sure that this mark is positioned toward the front of the tank, and insert the pump about half way. You will need to re-connect the electrical connection inside the tank, and the two vent lines to their correct locations on the pump base.

When the connections are complete, slowly move the pump up to the hole and look around to ensure that the O-Ring is in place, and that the pump is even all around.

With the holes lined up with the studs correctly, gently push around the lip of the pump to begin to insert the pump in place. Continue to push in until the pump is far enough in to re-fit the 13mm nuts that hold it in place.

Using the three nuts, slowly, and evenly tighten them to draw the pump into its fitted location. Torque the nuts to about 15-20 ft-lbs of torque.

At this point the tank should be removed from the bike, and refilled partially with gas to ensure that it does not have leaks. If it does, you will have to inspect your installation of the O-Ring. Restart from step 10.

If it does not have any leaks, re-attach the tank to the rear pin and put the tank on its prop rod.

Re-attach the fuel lines. Remembering that the line with the "R" is attached to the centermost spigot and the line with the "M" is attached to the spigot closest to the outside of the tank. Also, re-attach the fuel-overflow line that should be cable-tied to the "M" fuel line.

Re-connect the electrical connector to the fuel pump. Remove the paper-towels you laid down previously.

Lower tank back into position, and connect the rubber hold-down hook.

Re-attach the key guard.

At this point you should turn the key from the off to the on position a few times to allow the fuel pump to restore fuel to the fuel system. Wait approximately 5 seconds when key is in the on-position.

Start motorcycle and inspect for anomalies.

Ride!

More Notes:

After I was done, I was able to open the old fuel filter with a hand-can opener, to look at the filtering material. It was quite black. With the new filter installed the bike idles noticeably smoother. Also, it has been mentioned several times that people have had very bad luck with aftermarket fuel filters; it is advised at this point to stick to Ducati brand filters.