digiplex in combination with vacuum fuel pump

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Brutus
Posts: 257
Joined: Sun Jan 16, 2005 12:00 am
model: 750 Paso
year: 1989
Location: The Netherlands

digiplex in combination with vacuum fuel pump

Post by Brutus »

Gents,

Last couple of days I have had a go at the fuel pump. Installed the vacuum pump from a Yamaha and altered the fuel lines. Btw, my Paso is the Cali model with the digiplex. As you will probably know the digiplex is activated by the vacuum from the manifold. Two tubes are connected to the manifold, see number 49 below. These two tubes are joined together with a plastic T and one tube will continue to the digiplex.

Image

In my new setup I only used one connection for the digiplex (mainfold vert cyl) and one connection for the fuel pump (manifold hor cyl). My question is if this will effect the timing advancement from the digiplex. Don’t really know if the vacuum of both sides are needed.. Like to hear your opnion :thumbup:
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Brutus
Posts: 257
Joined: Sun Jan 16, 2005 12:00 am
model: 750 Paso
year: 1989
Location: The Netherlands

Re: digiplex in combination with vacuum fuel pump

Post by Brutus »

Here some pictures of the vacuum pump modification. Return line to the tank is eliminated. Startup is much approved. I'll have to test the setup of mains, idle jets etc. again
Attachments
old pump
old pump
Foto0954.jpg (146.32 KiB) Viewed 6283 times
yamaha vacuum pump fitted on homemade alu bracket
yamaha vacuum pump fitted on homemade alu bracket
Foto0961.jpg (169.45 KiB) Viewed 6283 times
new pump fitted
new pump fitted
Foto0965.jpg (123.25 KiB) Viewed 6283 times
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Brutus
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Joined: Sun Jan 16, 2005 12:00 am
model: 750 Paso
year: 1989
Location: The Netherlands

Re: digiplex in combination with vacuum fuel pump

Post by Brutus »

Here the new lines installed. The orange line is the vacuum from the right side of the manifold to the pump. The blue lines supposed to be the flow of fuel from tank to pump to weber.
Léon
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Foto0962.jpg
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paso750
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Re: digiplex in combination with vacuum fuel pump

Post by paso750 »

nice job. I don`t think it makes a difference for the Digiplex if it is only connected to one side of the carb manifold.
Afterall there might two connections only because of the necessity to connect a carb balancer.

G.
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Brutus
Posts: 257
Joined: Sun Jan 16, 2005 12:00 am
model: 750 Paso
year: 1989
Location: The Netherlands

Re: digiplex in combination with vacuum fuel pump

Post by Brutus »

Tx Gerhard,

I couldn't resist to have another go at the manifold. Below the current setup. Drilled a hole and fitted a third tube for maximum vacuum to the pump. I was considering to drill out the m6 bolt as shown in drawing above, nr 56. As you probably will know the left one goes through the manifold into the channel. I have a lathe, but this small tubing is a b%tch to create myself.
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Foto0971.jpg
Foto0971.jpg (179.15 KiB) Viewed 6202 times
Foto0973.jpg
Foto0973.jpg (159.45 KiB) Viewed 6202 times
Foto0974.jpg
Foto0974.jpg (188.42 KiB) Viewed 6202 times
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Brutus
Posts: 257
Joined: Sun Jan 16, 2005 12:00 am
model: 750 Paso
year: 1989
Location: The Netherlands

Re: digiplex in combination with vacuum fuel pump

Post by Brutus »

Gents,

This is how she runs right now. Pretty pleased with the result. She starts at the first turnover and she responds better between 0-3500 rpm.

https://youtu.be/1wynNtc5p3g


Ducati 750 paso Cali model

Ignition:
- Stock Digiplex, stock connection vacuum lines to manifold
- Stock flywheel and pickup sensor
- Ducati 996 coils, added superseal connectors to wiring loom
- Red ngk spark plug wires and caps
- iridium spark plugs ngk DCR8EIX, gap at 0,9mm

Fuel supply:
- stock petcock
- universal fuel filter
- vacuum Fuel Pump For Yamaha (XVS125, XVS250,TDM850)
- extra vacuum line between right side manifold and fuel pump
- homemade bracket for vacuum pump

Weber:
- idle jets 60
- main jets 145
- air correctors 175
- idle adjustment screw 4 turns out (4 x 360degr)
- air adjustment screw: left closed, right approx 1 turn out
- float level 43mm (with gasket)
- stock aux 3,5 venturi
- aftermarket K&N airfilter
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