Fuel Pumps

[phildawson8270]

Ok,

So I know that bikes like the 98-02 R6 had a low pressure fuel pump that delivered fuel from the tank to the carbs as the tap is too low for a gravity feed.

Now, on my GSX-R 400 I am running a false tank, underneath will be a small 6L tank.

However, as I am running total loss and plan on running a smaller battery, I will have a lot of space in the rear subframe, and especially under the seat. I was thinking that I could quite nicely put a fuel tank there, but it will be lower than the carbs so will require a fuel pump to deliver it.

What options do I have for this? Is there any issues with using a low pressure pump from something like an R6 on a carb not designed with this in mind?

If that's a no-go, I assume then a 1L swirl pot above the carbs, that is fed by the pump is the next choice?

[kanerdog1x1]

part of the reason a r6 uses a fuel pump is to deliver the amount of fuel it needs on full chat. i used to spanner for a lad who raced a pair of fzr400s in new era, and his bikes had mechanical fuel pumps in them. low pressure facet ones from a land rover. not too hungry on 'lectric, and very reliable. cheap too. worked fine with the floats in both the normal carbs in the wet bike and the flatslides in the dry bike.

[halfmanhalfninja]

+1 for the Facet fuel pump, done some research on these as my track 7r pump is fuckin abaht.

Standard pump is rated at 2.5 to 3.5 psi, so would need one of the lowest rated, like this...

http://www.ebay.co.uk/itm/FACET-POSI-FLOW-FUEL-PUMP-1-5-4-0-Psi-10mm-UNION-FILTER-/270587436561?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item3f00449e11

I was told about them by a mate that races a Radical (its a kit car, apparently) with a ZZR1100 motor and he used this pump with no issues.

[phildawson8270]

It's to feed a 400 engine, so if it can handle 1100cc at full power in a kit car, then it should be suitable for supplying a 400cc engine at full throttle.

The only other question is whether anybody knows the kind of expected current draw? As the bike will be total loss, so I don't want to kill the battery before the end of a session.

[thefatman]

It's very low. Running total loss the battery willl last a good few 20 minute sessions, possibly all day. Put it on an optimate or swap batteries at lunchtime if doing trackdays.

[Superdunc]

If you a Facet or similar, you'll need a pressure regulator. I'm sure an early SV650 pump would be more suitable.

[phildawson8270]

So the facet pumps that say 1-4psi will just run constant 4psi but can be regulated down to 1psi with the use of a regulator?

[Superdunc]

So the facet pumps that say 1-4psi will just run constant 4psi but can be regulated down to 1psi with the use of a regulator?

yes.

[phildawson8270]

Part of me thinks that 4psi will be fine for the carbs? Though I suppose the only way to find out for certain is see what comes out of the overflow lol!

[2moto]

Part of me thinks that 4psi will be fine for the carbs? Though I suppose the only way to find out for certain is see what comes out of the overflow lol!

I reckon you're right. You might have to lower the static bowl height slightly to compensate but even that's not needed. Maybe do a bench test first.

[Guest]

What do you do with the overflow? Route it back to the tank?

[lorenzo]

I'm sure an early SV650 pump would be more suitable.

I'm also 90% certain that early SV650 pumps were vacuum operated, rather than of the leccy, thereby saving you a bit of battery life.

[Superdunc]

What do you do with the overflow? Route it back to the tank?

You mean for the pressure reg? Low pressurecarb regulators, don't have a return like a Fuel injection regulator.

[kanerdog1x1]

Hang on, the facet pumps we used to use didn't need a regulator? They go like the clappers when the ignition switches on, then drop down to a stop when the pressure get up, after 2-3 seconds. Then when the bike starts they click every 3-4 seconds at tickover, you can't hear it, but you can feel it if you put your hand around the pump.

These:- http://www.facet-purolator.com/cube-fuel-pump-kits.php

[Superdunc]

Hang on, the facet pumps we used to use didn't need a regulator? They go like the clappers when the ignition switches on, then drop down to a stop when the pressure get up, after 2-3 seconds. Then when the bike starts they click every 3-4 seconds at tickover, you can't hear it, but you can feel it if you put your hand around the pump.

These:- http://www.facet-purolator.com/cube-fuel-pump-kits.php

Ah. They're not the ones I had in mind.

[phildawson8270]

So what is the difference between that cube one, and the posi-flo ones?

The posi-flow pump also states 1.5A that is quite a lot of current to be drawing, so I guess it's going to be battery charging between sessions?

You mean for the pressure reg? Low pressurecarb regulators, don't have a return like a Fuel injection regulator.

Yes I know that. But if the overflow from the carb needs to be fed into a catch tank, I may aswell run it back to the fuel tank.

[2moto]

So what is the difference between that cube one, and the posi-flo ones?

The posi-flow pump also states 1.5A that is quite a lot of current to be drawing, so I guess it's going to be battery charging between sessions?

Yes I know that. But if the overflow from the carb needs to be fed into a catch tank, I may aswell run it back to the fuel tank.

The Ebay link states:

POSI-FLO’s new design replaces the older Facet cube solid state pump in all applications. With this new design, the pump is quieter, very reliable, and is rated for 6000 hours.

The older solid state Facet were noisy buggers, never liked them. I'd go with newer, replacement Posi-flo type. You shouldn't need a regulator. the overflow can be routed to a catch tank or back to the tank. I'd use an overflow bottle to avoid any tank venting/pressure issues.

[phildawson8270]

Agreed on venting issues, I'll just go to a catch tank

Thanks guys