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Help Fuel Pump Pressure?

Discussion in 'Yamaha 250cc In-Line 4's' started by maelstrom, Apr 13, 2022.

  1. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    My Bike:
    Yamaha FZR400 3TJ1, Honda MC22
    I assume the 250 is not much different that the 400, so does anyone know how many psi the standard pump flows? I would like to use one of these instead of the OEM part https://www.facet-purolator.com/cube/ but I need to sort out what the OEM one does first.
    This is from the FZR600

    FuelPump_02.jpg
    I have a Chinese version of the OEM pump and it just runs continuously when connected directly to power, so it appears the 5 second cyle is coming from the TCI unit.
     
  2. Murdo

    Murdo The Good Doctor Staff Member Contributing Member Ride and Events Crew

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    I can only tell you of my experience with the CBR's.
    They run at about 1 to 1.5psi at shutoff (measured with low pressure gauge) and will run all day without any back pressure (when needles shut in carbs) until pressure is achieved, then shut off until fuel is used and pressure drops and they will run again to build pressure. The power to the pump is through a relay under the seat that is controlled by the ecu, and will not power the pump until engine rotation is sensed and will cut power if engine is not rotating (ie you have fallen over or stalled engine).
    I have used those facet pumps in the past in my racing cars and found them very limited in their flow rate (which is a problem with most electric pumps) and the one shown may be too big for a bike engine.
     
  3. maelstrom

    maelstrom LiteTek Staff Member Premium Member 250cc Vendor Contributing Member

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    Thanks @Murdo. That sounds like the similar setup to the Yamaha. Perhaps they use the oil pressure switch circuit with a bypass on startup in the TCI. It sounds like the pressure cutoff has to be in the pump.
    The Facet 40163 is 1.5 to 2.5 psi and 17 gph.

    Edit: Looks like the "Main Relay" assembly is a collection of diodes and relays to ensure that a correct combo of neutral/clutch/sidestand etc is enabled before you can crank the engine and allow the TCI to supply power to the fuel pump.
     
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    Last edited: Apr 14, 2022

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