speedysprocket
Alex
- Location
- Chesapeake, VA
Good point, seems the needle seat is the restricting factor here. If your pump can force the necessary fuel volume through that tiny hole, it should have zero problem pulling fuel through a 1/4" fuel line.
Custom/Hybrid Dual Fuel Pickup...reason?
- Thread starter jetpilot808
- Start date
- Location
- South Africa
And each pump draws on their own stroke so actually each pump is using the fuel-line for itself at any one time
- Location
- South Africa
Check the size of the pickup in the tank, some of the clunks in the kart tanks have to be drilled out
- Location
- USA
Has anyone have fuel starvation due to one pickup? (on a big motor)
- Location
- USA
I was thinking the same thing, carb has enough restrictions, even at high pressures, to be supplied with a single 1/4" (6.35mm) line.
Now, if I invest high dollars into a motor, I probably would not take a chance. But for most of our applications and styles of riding, it is sufficient to run just one.
mattyboy89
The countdown is on
- Location
- Kamloops BC Canada
MATH IS AWESOME!!!
So for duals with individual pumps the flow rate would be doubled essentially, hence the reason dual pickups are used.
Simply to keep the supply to the dual pumps instead of trying to pull that sort of flow rate through a single 1/4" feed.
The one pump may flow 65 litres per hour and return 50 of that, the fuel used by the engine is determined by the carb settings which is irrelevant.
The reason the mikuni pump pumps 65 lph is simply because it's run of a constant pulse and can't be regulated like a mechanical pump would, so in saying that Slave dual carb set ups don't require a dual pickup because one pickup is sufficient for a single pump dual slave setup, it's when you start getting into the big cc engines that the fuel required from a slave system is insufficient and a dual pump setup is required fed by individual pulse lines and individual feeds from a dual pickup.
Correct me if I'm wrong but that's my take on it
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Simply to keep the supply to the dual pumps instead of trying to pull that sort of flow rate through a single 1/4" feed.
The one pump may flow 65 litres per hour and return 50 of that, the fuel used by the engine is determined by the carb settings which is irrelevant.
The reason the mikuni pump pumps 65 lph is simply because it's run of a constant pulse and can't be regulated like a mechanical pump would, so in saying that Slave dual carb set ups don't require a dual pickup because one pickup is sufficient for a single pump dual slave setup, it's when you start getting into the big cc engines that the fuel required from a slave system is insufficient and a dual pump setup is required fed by individual pulse lines and individual feeds from a dual pickup.
Correct me if I'm wrong but that's my take on it
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Draggingto
No Clue
- Location
- Brooklyn MI
After reading all this I have a question. Does it hurt anything to run dual pickups, say your motor doesn't need all that much fuel and a single line would be sufficient. Are there drawbacks, worse fuel economy, or would it just return that much more to the tank since it's pumping but being unused?
- Location
- CT
Does I hurt no. But can it hurt yes.
1 fuel like and the pickup gets clogged you know right away when it runs like poo.
2 fuel lines and 1 clogs you may feel it not run right or not. Or you may think its a number of other things.
Now for pulse line. Yes run 2 and make them even so they have the same pulse.
1 fuel like and the pickup gets clogged you know right away when it runs like poo.
2 fuel lines and 1 clogs you may feel it not run right or not. Or you may think its a number of other things.
Now for pulse line. Yes run 2 and make them even so they have the same pulse.
- Location
- USA
Right, the unused fuel would just get returned to the tank. And I don't think you would burn anymore fuel either. I always worried about getting uneven amount of fuel to one cylinder (blockage) ,If single line gets blocked, your motor stops. If one of dual lines gets blocked, one cylinder goes lean without possibly knowing, and you are risking seisure. Plus, I found it interesting....so many people spending a pretty penny on dual pickups for standard size motors. Just wanted to throw it out there, lot of mixed feelings for sure.
- Location
- South Africa
Agree
In a single line feeding duals the momentum of the fuel flowing from the one pumps pulse helps the other pump in its pulse. A single line feeding a single carbs has the the fuel flowing in gulps.
The one factor that can skew things is the length of the pipe, the longer it is the more resistance to flow, but on freestyle skis and kart tanks they are normally fairly short compared to race skis with the oem tank locations. If I remeber correctly, Resistance in a pipe = Length divided by the Diameter to the Power of 5
- Location
- Cruising Around
That number you are giving for flow rate, that is for an SBN body mounted pump? Or is that flow rate for the Mikuni DF62 remote pump that has a larger inlet and 2 outlets?
- Location
- CT
Remote. I think if I remember right the sbn body was 55 or 60. I remember thinking why would people use them if they were that close