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496 Posts
Discussion Starter · #1 ·
My buddy Dave's ST4 started running poorly, as if a number of ponies would not show up the party. The PO of the bike had replaced the in tank fuel hose - which he told Dave when Dave bought the bike - as part of a fuel filter change.

Well, the guy used the wrong hose. When we took the fuel pump assembly out of the tank, the hose had all but disintegrated and was a gooey blob of a mess. Inside the tank were gooey pieces of hose and some paint chips, with hose residue all over most of the pump assembly. It took quite a while to clean everything up with Berkbile carb cleaner, https://www.berkebileoil.com/instant-gum-cutter.html plastic scrapers and some lacquer thinner.

Here's a decent vid on how to do it but note that you will need over two feet of hose - there are three hose lengths in all. One shorty on the pump assy and two in the tank itself.

Using regular fuel line is what caused this mess. Sure, it will last for awhile, but it will not stand up to the fuel in the long term. Ducati wants a fortune for the fuel hose, but there are cheaper outlets for the same stuff. It is still nevertheless expensive and for good reason. The proper hose is:

Gates 27097 Submersible Fuel Line Hose - or SAE hose part number 30R10

It is $18 per foot and you can only buy 1' sections for some reason. You need 5/16" ID by the way. So, for about $60 you can fix the mess if you have the same problem.
Couple of notes - use a sturdy plastic scraper/pry tool to get under the fuel pump flange when removing the fuel pump from the tank and be extra careful not to bend, ding or distort the flange as this will result in a leak. Replace the green rubber sealing O-ring also, which is all that is keeping the pump assy sealed to the tank. The aftermarket fuel filter that we used was too small in OD to fit the nylon mounting ring's ID, so we safety wired a split pc of the submersible tube to take up the difference. Do not of course use regular rubber whatever to do this.
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496 Posts
Discussion Starter · #2 ·
If the vid does not come up as it often does for me, here's the YouTube link

496 Posts
Discussion Starter · #3 ·
In the interim, Dave sent me a more complete post for the sources and uses of the above fuel hose.
To wit:
Use ONLY SAE 30R10 hose. All of the other SAE specs will turn into chewed up black gummy bears as shown in the attached photo. The second photo shows a new hose (u-shaped) installed.

5/16" (8mm) hose required:
2-12" straight lengths for the fuel pickup hose, and the fuel return hose. Both of these run to the bottom of the tank.

1- 6" to 7" length (from fuel pump to filter (bend in U-shape)

1- 2" to 2-1/2" straight length from outlet of fuel filter to the circular aluminum manifold that bolts into tank (use new Viton O-ring to remount this fuel pump assembly.

Total length required is 36". The little bit of excess that remains can be used to cut a spacer to fit around a NAPA Gold 3032 fuel filter (instead of the expensive Ducati filter) so that it will fit in the plastic fuel filter holder.

Best pricing I found is as follows:
Euromotoelectrics (For BMW 1 meter length of 8mm for $39.00 with priority shipping. This comes to $12 per foot.


Other sources are:
$17.88 for 12" length with free shipping with Prime. 3 lengths of 12" = $53.64 total.

Rock Auto which has the cheapest pricing but you have to pay for shipping. They only sell in the following quantities.
1-12" length at $15.10 ea. (Gates 27093)
10' length at $13.07 per foot (Gates 27080)
32' length at $12.88 per foot. (Gates 27083)

10' to my address from RockAuto with shipping and NJ Sales Tax is $146.81 or $14.68 plf.

AC/Delco and Enduralast also produce this hose, but they are quite a bit more expensive than the above.

Submersible vent line. There is a smaller vent hose in the tank that looks a bit dried out.


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