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2021-01-07 Fuel Delivery Problems

dcarver's picture
published by dcarver on Thu, 01/07/2021 - 09:47
Forums: 
1979 KZ1300 A1 Kawasaki

 

‘Calibrated’ fuel gauge by filling tank, then draining 1 gallon per time. Surprising, I know, but the fuel gauge is completely non-linear. Imagine that. 
 
Worse yet, after 4 gallons drained on a 5+ gallon tank.. no more fuel delivery. On the KZ, tank outlet and carb inlet.. maybe .5 inches.. 

2021-01-07 KZ1300 Fuel Delivery Issues from dcarver220b on Vimeo.

Back in the day, ran a fuel pump and regulator. May have to re-think this idea. Problem back then was the regulator, at minimum, exceeded float/seat and would flood out.

Running Pingle petcock. Cleaned it up. Not running external filter or quick disconnect fitting externally to minimize flow resistance.

My tank will be sent off for professional cleaning and sealing.

Fuel line routing.. Is there consensus as to most efficient route? Mine currently goes between throttle cables, around valve cover to inlet. Using MotionPro fuel line,
it's very flexible and stout. 5/16" ID.

At the inlet.

At the 'bend around the corner, RHS of bike.

Gauge calibration and flow delivery test. Nothing after 4 gallons, even on reserve.

As she sits. Installed soft saddlebags. Looking to purchase some portable plastic gas cans to carry extra fuel.

Went for a ride, the ol gurl did good!  

Questions, need advice please...

  1. Best fuel hose routing?
  2. Thoughts on running pump/regulator? If yes, any particular setup works well?
  3. Does your tank fully drain?

Thanks in Advance,

dCarver

Submitted by dcarver on Thu, 01/07/2021 - 11:06.
I have at last solved all the problems I had with fuel delivery. I fitted a Pingel fuel tap and turned it so the outlet faces towards the back of the bike, I also turned the fuel inlet "T" upwards so the fuel line connects from above. This set up gives me a fuel line not much more than 6 inches long, and it tucks up neatly under the bottom rim of the tank. I thrashed it up the motorway today, all the way from the Forth road bridge to Perth and back again with no sign of the power dropping off. At the moment I am relying only on the gauze filter on the Pingel fuel tap, and I have not fitted an in line filter. That said my tank is almost like new inside with no signs of rust or debris, I think it was treated with some kind of sealant when it was new.

IMG_2172.JPG


IMG_2173.JPG

Submitted by dcarver on Thu, 01/07/2021 - 11:08.

Link

Fuel line routing and fuel delivery.
I have at last solved all the problems I had with fuel delivery. I fitted a Pingel fuel tap and turned it so the outlet faces towards the back of the bike, I also turned the fuel inlet "T" upwards so the fuel line connects from above. This set up gives me a fuel line not much more than 6 inches long, and it tucks up neatly under the bottom rim of the tank. I thrashed it up the motorway today, all the way from the Forth road bridge to Perth and back again with no sign of the power dropping off. At the moment I am relying only on the gauze filter on the Pingel fuel tap, and I have not fitted an in line filter. That said my tank is almost like new inside with no signs of rust or debris, I think it was treated with some kind of sealant when it was new.

IMG_2172.JPG


IMG_2173.JPG
 

 

Submitted by dcarver on Thu, 01/07/2021 - 11:36.

Pegasus Racing

Submitted by dcarver on Tue, 01/12/2021 - 13:54.

 

paulb wrote: I know im going against the flow here[no pun intended]but is the length of fuel hose so crucial, surely once the fuel line is full as long as there is plenty of fuel in the tank it shouldn't make a difference to the fuel delivery, but then again my lack of technical knowledge is legendary.


The real issue is lack of head pressure when the tank is low on fuel. Just guessing, but the height differential is maybe 1 inch? Given that a water column 27.72 inches generates 1 psi, then each inch of height generates .04 psig, not much.

And that's for water, which has a specific gravity of 1. Gasoline has a specific gravity of .739 which is why 1) gasoline floats on water, and 2) the resultant pressure drops to .027 psig.

So pretty much any flow obstruction (angled fittings, fuel filter, hose length and/or routing, tank not venting) will prevent the tank from fully draining.

Playing the numbers, roughly, when the tank is full, the height differential from fuel level at top to carb inlet is maybe, perhaps 7 inches or so? At 7 inches, .19 psig is generated. It's a wonder these tanks drain at all.

Sure hope my math is right..

Of note, these numbers based upon standard gravity.

 

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