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Discussion Starter #1
The last time I turned the ignition on on my 96 900, the pump didn't stop priming. I turned it off after about 15 seconds, then tried again. The pump still didn't stop. I haven't ridden or tried to start it since.

Any idea what could cause this, or if this ever happens normally? What normally switches the pump off? I've had the bike about a month and am not that familiar with it. As far as I know, it's pretty much stock.

Thanks!
Michael
 

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Any idea what could cause this, or if this ever happens normally? What normally switches the pump off?
No it's not normal, the pump switches on/off through a control relay that is normally open, you probably have a "sticky" relay.
 

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The Pump should run non-stop. There is a Y in the fuel line on the way to the carb with a restrictor (it'd not much of a restriction, about 4mm inside the 7mm hose. It runs straight back to the tank. Maybe this is a substitute for a regulator?

The pump in the 900 is the same as the 916 (maybe 851-888 too?) Fuel injection pump I believe and puts out a lot more pressure than a carburettor needs so this stops the pressure pushing the float needle off the seat. Maybe it was Ducati's way of reducing inventory!
 

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A split in one of the pressure hoses inside the tank?
 

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The Pump should run non-stop. There is a Y in the fuel line on the way to the carb with a restrictor (it'd not much of a restriction, about 4mm inside the 7mm hose. It runs straight back to the tank. Maybe this is a substitute for a regulator?

The pump in the 900 is the same as the 916 (maybe 851-888 too?) Fuel injection pump I believe and puts out a lot more pressure than a carburettor needs so this stops the pressure pushing the float needle off the seat. Maybe it was Ducati's way of reducing inventory!
My doesn't stop either, you can actually hear fuel trickle back into the tank. Mine has the Y in the fuel line. Believe me you don't want it to stop! Mine stopped whilst riding & got stuck on the side of the road:mad:. If you hear a buz it's a good thing.
 

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Only the FI bikes have a prime relay.The carb bikes pump runs whenever the ign. is on. The pump is a low pressure[approx.3psi.] and is not the same as the injected bikes. In other words,nothing is wrong unless the pump isn't running.
 

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Only the FI bikes have a prime relay.The carb bikes pump runs whenever the ign. is on. The pump is a low pressure[approx.3psi.] and is not the same as the injected bikes. In other words,nothing is wrong unless the pump isn't running.
I assumed that it was the same pump, as I went to buy one and CA-Cycleworks sell the 916 style pump for the 900SS from 91-07 and Superbikes up to 2004. I asked Chris about this and he said it works great. It didn't make a lot of sense to me at the time for a carb'd bike ands my pump was still going fine so I put it in the "more research required" bin

I just searched and got a Part Number of 430.4.002.1A (Superbike is 430.4.004.1A) for the carb models.

It seems weird however that if that pump was 3psi that they would go to all the trouble and expense of fitting the return system and high pressure fuel lines. I just had the Y apart as I had a fuel leak when I first turned on the bike after fitting FCR's, I had removed the fuel line and I must have disturbed the clip on clamps. There seemed like a hell of a lot of pressure for a system that is open to atmosphere via a not so restriictve restricter (I looked at it when I took the Y apart to change the clamps) It's internal diameter is big enough to supply fuel for a 2 litre car (about the same ID as 1/4 inch fuel hose) The stock pump must have some volume capacity, which doesn't say anything about pressure.

I'd love to know what the best pump is for the application. Has anyone used the 916 pump Chris sells? I have no reason to doubt him, he has been really helpful to me and I'd buy from him anytime.
 

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Only the FI bikes have a prime relay.The carb bikes pump runs whenever the ign. is on. The pump is a low pressure[approx.3psi.] and is not the same as the injected bikes. In other words,nothing is wrong unless the pump isn't running.

Didn't noticed it's a carb, I stand corrected. :rolleyes:
 

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Discussion Starter #9
Thanks to everyone for their replies. Perhaps an electrical connection is improving with some use after sitting unused before my purchase. It's always nice when something fixes itself! :D

Michael
 
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