750 Sport fuel pump

discussion about the 750 Sport and '89/'90 900SS, which share many mechanicals with the Paso series
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Maico88
Posts: 73
Joined: Sun Oct 05, 2008 1:32 am
model: 750 Sport
year: 1990
Location: Georgia, USA

750 Sport fuel pump

Post by Maico88 »

I modified my 750 sport to run with no pump and found to much variation from full tank to empty tank. After some research I found an in-tank pump available from NAPA auto parts. The part # for the pump I got is NFP P74069 The pump produces 7 PSI. It fits very well in the stock bracket with the stock rubber grommet. The pump has a 1 year warrenty against defects and can be found at any NAPA parts store. The price was $61.99. I am going to try it without a pressure regulator. If the is a problem I will post it.
Image
The top pump is the one that was in the tank and the bottom pump is the new pump.
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ducinthebay
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model: 750 Sport
year: 1990
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Re: 750 Sport fuel pump

Post by ducinthebay »

Looks like as close to a match as you could expect. Nice work.
the 7 psi shouldn't be a problem, and its probably close to stock. A common modifcation with the stock carb was to put in a pressure regulator at 3 psi. If you are running Dellortos, or other carbs, then 7 psi will be more than enough.

Make sure you put a T in your fuel line before the carb(s) and run the other leg back up into the tank. There are two stub outs in the middle of the tank. One is the return from the T, the other is the vent line.

Keep us posted.
Cheers,
Duc in the Bay
1990 750 Sport x2-Rosso Blanko (900ss copy) & Nuovo Nudo (Scrambler project)
1991 907 -mostly stock
2002 ST4s - Lots of mods.
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jcslocum
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Re: 750 Sport fuel pump

Post by jcslocum »

If you put the "T" in the line and use the return line then you will not need a regulator. This makes the system recirculate the excess fuel and won't allow the pressure to build in the carbs.
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Maico88
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Joined: Sun Oct 05, 2008 1:32 am
model: 750 Sport
year: 1990
Location: Georgia, USA

Re: 750 Sport fuel pump

Post by Maico88 »

I do have a T in the line to return fuel to the tank, and so far no problems. :lol: Thanks for the info. :lol:
carlopalmas
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Joined: Mon Jun 08, 2009 12:41 am
model: 750 Sport
year: 1990
Location: Italy

Re: 750 Sport fuel pump

Post by carlopalmas »

Hi!
Question on where to tie the T into the tank...
On the tank there are 2 stems
1 - Rifuito Cabur Waste Fuel
2 - Sfiato Breather Pipe

Which one do I hook the T into?

Thanks!
Carlo
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higgy
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Re: 750 Sport fuel pump

Post by higgy »

1 - Rifuito Cabur Waste Fuel
Ducati,making mechanics out of riders since 1946
There's no problem so bad that a little fixing can't make it worse! : )
If it ain't broke keep fixin it till it is
88 750
90 906
92 907ie
carlopalmas
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Joined: Mon Jun 08, 2009 12:41 am
model: 750 Sport
year: 1990
Location: Italy

Re: 750 Sport fuel pump

Post by carlopalmas »

Yeah.... that's what I thought... still running rich ;)
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jcslocum
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Re: 750 Sport fuel pump

Post by jcslocum »

carlopalmas wrote:Yeah.... that's what I thought... still running rich ;)
Which carbs??
carlopalmas
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Joined: Mon Jun 08, 2009 12:41 am
model: 750 Sport
year: 1990
Location: Italy

Re: 750 Sport fuel pump

Post by carlopalmas »

It's the original weber carb. I installed a K&N air filter as well. Also decided to do away with the T and add the fuel pressure regulator.

Image

You can see the new pressure regulator here
Image

Didn't know what to do with the vacuum tubes on the carbs so I kept the old tubing and joined them... figured this was a better short term soltion than just leaving them open.
Image

almost clear pic of the vent tubs at the bottom of the tank, need to run tubing for these in the next day or two.
Image

The other toys in the pics are my 2004 VRod which I bought because of the amount of "down time" I was experiencing with the 750 and my wifes 2007 Sportster.
Image
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jcslocum
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Re: 750 Sport fuel pump

Post by jcslocum »

You can't leave the vacuum open or the bike will run poorly and very lean.

First, the Weber is not a very good carb to work with. Dellorto's are the best solution or adapting some Mikuni's off of a monster or ss.

Has the carb been rebuilt or fiddled with at all?? Do you know how to adjust it?
carlopalmas
Posts: 18
Joined: Mon Jun 08, 2009 12:41 am
model: 750 Sport
year: 1990
Location: Italy

Re: 750 Sport fuel pump

Post by carlopalmas »

no idea how to adjust. i disassembled them last year and soaked, then gave to a shop where they also soaked... so they are clean but I think all the settings are gone. I was careful to measure number of turns etc with every screw... who knows what the shop did.

any idea how to adjust?
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Maico88
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model: 750 Sport
year: 1990
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Re: 750 Sport fuel pump

Post by Maico88 »

I posted a note about a NAPA replacement pump ( NFP P74069) in March of this year. At this time, I can no longer recommend this pump. The first pump I put in lasted about 5 weeks. NAPA replaced the pump at no charge. Unfortunately, the replacement pump failed last week. I have gone back to running the bike with no pump ( I have Dellortos). After readjusting the carbs, the bike is running well.
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higgy
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Re: 750 Sport fuel pump

Post by higgy »

How much for the old weber?
Ducati,making mechanics out of riders since 1946
There's no problem so bad that a little fixing can't make it worse! : )
If it ain't broke keep fixin it till it is
88 750
90 906
92 907ie
User avatar
Maico88
Posts: 73
Joined: Sun Oct 05, 2008 1:32 am
model: 750 Sport
year: 1990
Location: Georgia, USA

Re: 750 Sport fuel pump

Post by Maico88 »

I don't have the weber that came on the Sports. It had dellortos when I bought it.
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ducinthebay
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Re: 750 Sport fuel pump

Post by ducinthebay »

higgy,
If you want an old weber, I have one in a box, complete with manifolds and air cleaner. I had once toyed with the idea of returning my bike to stock, but went entirely in the other direction.$75 plus shipping from California.

Cheers,
Duc in the Bay
1990 750 Sport x2-Rosso Blanko (900ss copy) & Nuovo Nudo (Scrambler project)
1991 907 -mostly stock
2002 ST4s - Lots of mods.
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