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Hi,

I recently bought a 98 ST2 and the owner has barely riden it..When I switch on the key and put the run switch on, I hear a hissing noise from the tank and I know its my fuel pump building up pressure. I have a 916(Full arrow pipes) also and after I start its engine and raise it up, I dont hear the hissing sound.But in my ST2 I hear it. Is it normal or is there a problem?
 

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You might have a cracked or loose hose right after the fuel pump causing the fuel pressure to never reach the optimum pressure. Open your gas cap and see if you see fuel splashing around. Be careful of not getting any gas into your face in case the line is split.

-Fariborz
 

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Discussion Starter #3
Ok, This is what i did. I removed the gas cap and put the engine switch to on. The fuel pump came on and then i heard fluid splash in the tank. to check if this is normal, i did the same test in my 916 and found it was not splashing. So i think there is a problem, but is it a burst line...if so where can i find fuel lines, i would prefer one that is not OEM, so that it will not break again

Thanks,
 

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theductor said:
Hi,

I recently bought a 98 ST2 and the owner has barely riden it..When I switch on the key and put the run switch on, I hear a hissing noise from the tank and I know its my fuel pump building up pressure. I have a 916(Full arrow pipes) also and after I start its engine and raise it up, I dont hear the hissing sound.But in my ST2 I hear it. Is it normal or is there a problem?
not sure about the 916, but the ST will run the fuel pump when you you turn on the key. This is normal. It should turn back off after it's pressurized
 

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I have not verified this but next winter I am going to the BMW car shop to see if their in-tank fuel injection hose is of acceptable size to that of our Ducati.

I bought one in-tank hose and it was $27, the one below the fuel filter (like 2" long) was $4 and one of the out of tank hoses was $75. I did not get total prices but to replace them all it must be over $200.

There is no problem with the Ducati hose. They are good quality. The hose that I bought as a spare was made in Europe by Trelleborg. I have tried to buy a roll and part it out, but they are not interested in selling one roll.

Maybe the hose slipped off like the previous post or the hose will dry if it is not kept submerged.

Dave Harhay
 

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theductor said:
Hi,

I recently bought a 98 ST2 and the owner has barely riden it..When I switch on the key and put the run switch on, I hear a hissing noise from the tank and I know its my fuel pump building up pressure. I have a 916(Full arrow pipes) also and after I start its engine and raise it up, I dont hear the hissing sound.But in my ST2 I hear it. Is it normal or is there a problem?
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The sound you hear is normal...the hiss (is the pump), and a slight gurgling is the discharge from the air separator that's part of the pump set-up. If you hear/see a loud WHOOOSH, there's a chance that your line is split in the tank.
The 916 should be the same. If the tank is very full (on the 916?) you may not hear or see the gurgling.


Some early (1998) models had a recall for the fuel lines. It's done by VIN#. Bring it to a good dealer, and they'll check to see what campain updates were done to your ST2. Shift lever, hardened countershaft sprocket retainer, and the alternator stator were some of the upgrades. Funny, my own ST2 was not in the range of VINs that needed the fuel line, but it split on me anyway.

If it does split, the bike will have trouble running. The FI needs 40 ish PSI at the injectors, and a split line in the tank might get you 1 or 2 psi. I was able to "limp home", but just barely over closed-throttle is all the engine would do.
 

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The other thing is that the FI pumps need to run continuous. They don't shut off "when it hits the right pressure". They shut off when the delay tells the relay to shut down. Most cars are like this, too. The pump will run for about 2 seconds when the key is 1st turned on. If the engine is fired up, it will continue to run. The computer knows when the engine is running, and will keep the pump relay energized. If the engine stalls, the pump turns off again after the 2 sec. delay. It's safety related...you don't want to be pumping 40 or 50 psi petrol around a hot engine that might just have been in a wreck.

I had a 1995 916, and the pump did the same routine as the ST2.
 
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