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My 1999 ST2 just quit the other day, like it ran out of gas and it had 3/4 tank! I assumed the fuel filter was clogged and tore into the tank to replace it. As soon as I dropped the plate from the bottom of the tank, I saw a problem with all the internal fuel hoses. They were all very soft to the touch on the outside and crumbling apart. The bike only has 7600 miles and I assume the hoses are factory. The bike was sitting for a 1 1/2 years before I bought it and I planned on replacing the fuel filter, as a precaution anyway.
My question is, do I have to replace these hoses with SAE 30r10 spec. fuel line (submersible FI hose) so the hoses will not break down again? I've found 1' lengths of this type of hose in town, but it's $30 a foot! I don't want to spend all this cash on hoses, if I don't have to. Will regular fuel injection hoses work? The Ducati dealer can order all thoses hoses for me, but they all add up to $90 and the dealer couldn't tell me what the spec. of the hose was! The hoses in my tank are so bad, i don't see any designation on them. Has anyone run into this problem?

Thanks!
 

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Exactly the same problem happened to me about a month back! The hoses in my tank disintegrated and left me stranded in a lay-by. They crumbled to the touch. My dealer replaced them all and the fuel filter, with Ducati specification replacements.

My ST had been sat at the dealer for about 1 year (another story; not relevant here) with no gas in the tank. I suspect this was the main problem. The hoses in the tank are meant to be submerged in gas most of the time. Leaving them open to the air for extended lengths of time probably dries them up badly and hastens their demise! :D

When you replace your hoses, make sure you completely drain the tank first and then vacuum out the crap from the bottom of the tank. My mechanic said my tank had a lot of rubber residue from the failing hoses in the tank. You don't want that flaky crap clogging up your fuel filter!
 

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i just got a 98 st2 so i expect it needs hoses. i am waiting on some parts before i tackle the t belts, so i reckon to change the internal fuel hoses and fuel filter at the same time. i looked over the workshop manual and it says to empty the tank, but neglets to mention the best method to drain it. should i pull the lead hose to the throttle bodies?
 

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Discussion Starter #5
There is a drain plug on the back underside of the tank, near the mount plate. This is the easiest and best way to drain the tank! Pull all the hoses off the fuel pump assembly plate on the bottom of the tank before you pull the tank and empty it. There will be a small amount of fuel that remains in the fuel supply hoses when you pull them off, so have a rag handy! It's a very simple job to replace the hoses, but having a hard time locating submersible fuel lines in my city. I found some at Napa, but only sell in 1' lengths and it's $30 a foot! I guess I'll probably end up ordering the stock hoses from Ducati if I can't find a place to buy hoses off a roll in town.
 

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you might want to try a japenese dealer. i am going to pick up some parts for my dr650 early in the week. i will check there, any idea what size hose is required? the last fuel line i bought there was some soft gray stuff, no marking on it but it was around $5/ft.
 

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The hoses inside that tank have to be 5/16" braided fuel injection hose that is designed to submerge.
 

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it looks like spec sae 30r 10 is the hose, seems only gates makes it and only napa suppies it. not to many options, just pay and ride.
 

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sounds like a solid working solution. i just sent an order into d'times, it looks like i need more stuff already and another order.
 

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THe metric clamps are in mm sizes 12, 13, 14 etc. 1mm wrong for the hose used and they will not tighten properly. Pull on the hoses when you install them to make sure they are tight. I believe this is why we see posts relating to fuel lines blowing off in the tank after replacement, even from the dealers.
 

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Note that certain VIN range of ST models were subject to a "Ducati campain" (polite term for silent recall). You should check with your dealer to see if your VIN was affected, and if Ducati ever did the recall... If not, I'd say they owe you!

These campaigns are performed for free...

It's a good idea to check anyway to see what campaigns might have been for your bike, and if they were performed or not.

My 1998 had:
1) shifter lever upgrade,
2) hardened drive sprocket retainer washer
3) Alternator Stator
(my VIN was out of the range for the fuel lines--but it popped on me a couple of years later regardless. The only nice thing about this is that it happens inside the tank...)
 

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I recommend the SAE30R10 hose since it's the only one rated for submersible applications. Darn stuff is expensive, from $23 to $30 per foot, and only sold in 1-foot lengths. You found it at Napa; I also found it at O'Reilly's. The hose on the Desmotimes website isn't rated for inside the tank. LT just recently changed that. There are several threads on the Sport Touring list about changing out fuel filters and lines in the tank. Just do a forum search for "fuel hose" or "fuel filter".

If you're having problems with the bigger hoses that handle the vent and overflow you may also want to replace the 2 molded hoses on the pump assembly. These are the smaller ones. I don't know any source except Ducati. Those hose clamps by Ideal referenced by Jeff_Tippett can be found at O'Reilly's Autoparts. You might be able to get them elsewhere too. Just be sure to get the 5/16ths version.

Here's my parts list:
1. 3 of the 1 foot pieces of the SAE30R10. Use 2 for the vent and overflow from top of tank to bottom. Cut up the 3rd piece for the 2 short bits attached to each end of the fuel filter on the pump assembly. (Source from Napa or O'Reilly's)

2. The two small molded hoses from Ducati. The part numbers for the ST3 are 590.1.059.1A and 590.1.058.1A. They are attached to the air separator. (Source from Ducati)

3. Fuel Filter (Source from Desmotimes or Ducati)

4. O-ring. Just in case the old one is damaged or gets damaged while you're putting the assembly back into the tank. (Source from Desmotimes or Ducati)

5. 8 of those Ideal or equivalent fuel injection hose clamps. You need 8 just for inside the tank. (Source from O'Reilly's)

Bill W.
 

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My 1999 ST2 ran fine when I winterized it last fall, but wouldn't start this spring. The electrical system is fine. I finally had time to pull the fuel pump assembly from the bottom of the tank and found all of the "submersible hoses" were crumbling.

I've cleaned out the tank, which looks pristine inside with no rust or scale, and I have to order some SAE 30R 10 hose, as the nearest Ducati dealer or mechanic is 220 miles from my home. (I've read in other threads that the hose LT sells is not rated "submersible," and I don't want to be tackling this ugly job again in three or four years.)

I bought a NAPA fuel filter, as recommended in LT's manual. However, I cannot find a decent photo or diagram of the entire fuel pump/filter assembly for when it's time to put everything back together in either the LT book or my service manual.

Does anyone have a photo of the completed assembly for the ST2? It appears to me that in addition to the crumbling hoses, one of the high pressure lines which attaches to the fuel pump had blown off, and I want to be sure that I route all of the hoses properly.
 

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i think i finally got what i need to do this job, i just missed the breather and vent hose in the parts breakdown which was shown with the tank not the pump. i can see getting to the bottom clamps for the breather and vent hose but what about the clamps attached to the top of the tank, can i get my hand in there to detach and attach the upper clamps?
 

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Thanks va duc! Does the port on the top of the air separator assembly stay open?
 
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