alternative fuel pump

discussions specific to the 906 Paso
redchubeka
Posts: 35
Joined: Mon May 24, 2010 9:25 pm
model: 906 Paso
year: 1990
Location: Lago Maggiore - Italia

alternative fuel pump

Post by redchubeka »

I would like to have another fuel pump in my shelf.

do you think is better to buy an original used fuel pump on ebay or a new alternative is available?

grazie
Ducati Paso 906 grey 1990
Bmw K100rs 4v rot metallic 1992
Aprilia Tuareg Rally 1986
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paso750
paso grand pooh-bah
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model: 750 Paso
year: 1987
Location: southern Germany

Re: alternative fuel pump

Post by paso750 »

you could get a vacuum fuel pump from a Yamaha TDM/TRX or one from a Ducati Monster instead of an electric one. They work fine with the Weber. You only need to connect it to the underpressure connection on the carb manifold.
redchubeka
Posts: 35
Joined: Mon May 24, 2010 9:25 pm
model: 906 Paso
year: 1990
Location: Lago Maggiore - Italia

Re: alternative fuel pump

Post by redchubeka »

sounds good....

do you have some codes / articles numbers / or similar ... just to never buy the wrong one... :-P

many thanks paso750, you are always ready to answer at every question posted...
Ducati Paso 906 grey 1990
Bmw K100rs 4v rot metallic 1992
Aprilia Tuareg Rally 1986
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paso750
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Re: alternative fuel pump

Post by paso750 »

this is the Monster fuel pump
Image

a picture from Lanes bike
Image

the Yamaha TDM/TRX fuel pump which I prefer as it`s easier to mount and has all connections on one side
Image

a pic from my bike
Image

Monster pump left, Yamaha pump right. Both are made by Mikuni.
Image

The advantage compared to the original fuel pump is that it doesn`t draw any power and there`s no need of a fuel pressure regulator.

G.
redchubeka
Posts: 35
Joined: Mon May 24, 2010 9:25 pm
model: 906 Paso
year: 1990
Location: Lago Maggiore - Italia

Re: alternative fuel pump

Post by redchubeka »

I didn't known this kind of fuel pump...
do you think that buy an used one is a good choice?
g.
Ducati Paso 906 grey 1990
Bmw K100rs 4v rot metallic 1992
Aprilia Tuareg Rally 1986
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ducinthebay
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Re: alternative fuel pump

Post by ducinthebay »

Vacuum fuel pumps are common in snowmobiles and jet skis, where the fuel tank is usually lower than the carb.

Edit - Oh, and chainsaws, and lawnmowers too. (though probably not enough volume for your Ducati)

Cheers,
Phil
Last edited by ducinthebay on Fri Jul 18, 2014 4:52 pm, edited 1 time in total.
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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paso750
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Re: alternative fuel pump

Post by paso750 »

I`ve bought 5 used fuel pumps in the past. All are still in use and working. (Two in Australia, one in NZ and two in Germany). There`s not much that can break down on a vacuum pump. It´s just the membrane and if the pump is installed properly with a fuel filter before it there`s nothing to worry about.
I personally don`t have any concerns buying a used one.
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redchubeka
Posts: 35
Joined: Mon May 24, 2010 9:25 pm
model: 906 Paso
year: 1990
Location: Lago Maggiore - Italia

Re: alternative fuel pump

Post by redchubeka »

sounds good, but only one more question: which pressure and flow they have or must have to work on a paso?
Ducati Paso 906 grey 1990
Bmw K100rs 4v rot metallic 1992
Aprilia Tuareg Rally 1986
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paso750
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Re: alternative fuel pump

Post by paso750 »

I knew that but can`t remember at the moment. If you get the one from the Monster or the Yamaha you won`t have any issues on a Paso. The Yamaha TDM/TRX are 850cc 2 cylinder bikes and the fuel pump of the Monster was used on the 750 and 900CC engine.
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ducapaso
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Re: alternative fuel pump

Post by ducapaso »

Very small pressure. 0.3 bar (4 P.S.I.) if I can remember correctly. In example, fuel pumps for elder Mini were ok or any made for carbed engines, 0.2(3 P.S.I.) or 0.5 (7 P.S.I.) can fit with no problem at all.
Anyway there's a big difference with EFI fuel pumps that work @5 bar or more (70 P.S.I.)
have a nice ride, Nicola

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ex...Red "smooth" 753349 :-(
GuinnessDave
Posts: 31
Joined: Mon Mar 03, 2014 1:29 am
model: 750 Sport
year: 1990
Location: Savannah, Georgia, USA

Re: alternative fuel pump

Post by GuinnessDave »

So how do these vacuum pumps work? Where is the negative pressure draw coming from? I might have to try this. Did you just make a bracket and attach the pump to your frame? Ps i have the 750 Sport.
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ducinthebay
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Re: alternative fuel pump

Post by ducinthebay »

The vacuum line is attached to the intake manifold. There may be a brass nipple threaded in on both of them. They may be tied together with a T, and run back to the Digiplex for vacuum advance. Add another T into the line, and run it to the vacuum pump. The pulses of the negative pressure activates the diaphragm to move back and forth, and there are two one way valves to make it a pump. Mount the vacuum pump where ever you can. Plenty of room on the Sport.

Cheers, Phil
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.
pate
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model: intending to buy a Paso/Sport
year: 1985
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Re: alternative fuel pump

Post by pate »

Hi,looking for reassurance :shock: my bike is fitted with a pair of 900 ducati carbs from a monster I think, I presume that I will be able to use the fuel pump as well.

Cheers
Allan
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paso750
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Re: alternative fuel pump

Post by paso750 »

Allen, no idea why noone replied. The answer is yes, of course.
Fulvia-hf
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Joined: Sun Jun 06, 2021 1:19 pm
model: 906 Paso
year: 1989
Location: Netherlands

Re: alternative fuel pump

Post by Fulvia-hf »

I would like to reopen this interesting thread.
Is it a recommendable upgrade for my 906 to replace the operational electric fuelpump (with return line) with a vacuum operated fuel pump? And if so what will I notice when I do this? At the moment my 906 runs pretty decent. No irritable flat spots, sputtering or other carb issues to be noted.
Cheers,
William
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