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 Post subject: FCR's on a750 sport
PostPosted: Sun Apr 20, 2014 3:05 am 
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Joined: Sun Apr 13, 2014 3:37 pm
Posts: 4
Location: USA
model: 750 Sport
year: 1990
I am hoping someone can either direct me to some photos of the carbs installed, or just post some to this post. I am also looking for any setup and tuning info for this conversion.

Thanks!


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 Post subject: Re: FCR's on a750 sport
PostPosted: Sun Apr 20, 2014 6:45 am 
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Joined: Tue Mar 13, 2012 9:02 am
Posts: 315
Location: The Blue Mountains, NSW, Australia
model: other
year: 1988
viewtopic.php?f=13&t=6512

Also make use of the search function as well, there are several very good threads on the FCR's, and various other ways of mounting them.

Cheers and Welcome to the site

Peter

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www.pdbcustomguitars.com.au


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 Post subject: Re: FCR's on a750 sport
PostPosted: Sun Apr 20, 2014 6:39 pm 
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Joined: Sun Apr 13, 2014 3:37 pm
Posts: 4
Location: USA
model: 750 Sport
year: 1990
Peter,

Thanks so much. I am trying to figure out if the FCR's will be lower than the standard petcock ocation, it looks like they will be. If that is the case I can eliminate the fuel pump and its associated excess plumbing and let gravity feed the carbs. I will need to make a couple cuts inside the tank to achieve full use of the tank capacity, but that can be easily done. Any thoughts on this approach?

Lee


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 Post subject: Re: FCR's on a750 sport
PostPosted: Sun Apr 20, 2014 10:22 pm 
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Joined: Tue Mar 13, 2012 9:02 am
Posts: 315
Location: The Blue Mountains, NSW, Australia
model: other
year: 1988
Hi Lee,

I did post a more detailed reply, but it appears to have disappeared into the ether.

The upshot of it was I don't believe it will make enough of a difference to the tank capacity to be worth it, Ducinthebay has been down this road I think?

Cheers

Peter

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www.pdbcustomguitars.com.au


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 Post subject: Re: FCR's on a750 sport
PostPosted: Mon Apr 21, 2014 8:34 pm 
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Joined: Sun Apr 13, 2014 3:37 pm
Posts: 4
Location: USA
model: 750 Sport
year: 1990
I just believe in the KISS principle - keep it simple stupid. The less there is to go wrong the less that will go wrong. The fuel pump pickup point is essentially at the same elevation as the petcock so I would not be losing any tank capacity but would be losing a little weight and certainly some complexity. And since I no longer have the Weber carb to have to pressurize the pump is unnecessary. One rubber plug will seal up the return line and the vent is necessary anyway.

So two cuts with a small cutoff tool and the deed is done.

This bike has already gone thru one fire, I would like to eliminate/minimize the possibility of a second one. Leakage thru a needle/seat is always a problem with a carb but much more so when pressurized to boot - and with an electrical pump versus a mechanical one, since it will run even if the engine is not running.


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 Post subject: Re: FCR's on a750 sport
PostPosted: Tue Apr 22, 2014 7:15 pm 
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paso grand pooh-bah
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Joined: Sat Sep 03, 2005 12:00 am
Posts: 1309
Location: SF Bay Area
model: 750 Sport
year: 1990
I am running the fuel pump, and also a T in the line by the carbs to return the excess pressure back up to the tank. I didn't use any flow restrictors. This way the pressure is the same whether your tank is full or near empty. I eliminated the petcock all together and went with a banjo fitting, as the threads on the tank are 10 x1mm and a standard banjo bolt works fine. (used on lots of later model ducs) .

Gravity worked fine for many years, but a fuel pump is just a bit more consistent fuel pressure. Added bonus, the fuel pump and the recirculating works nicely to mix the fuel if you occasionally use additives like octane boosters or Sea Foam type of products.

FWIW

Cheers, Phil

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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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