Why did Honda place the VFR fuel pump INSIDE the fuel tank?

Discussion in 'General VFR Discussions' started by Kalikiano, May 7, 2021.

  1. Kalikiano

    Kalikiano New Member

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    I've been dying to ask this question ever since I took it into my mind to replace the existing 2002 VFR800A fuel pump on my bike...only to find that both the pump and the filter are situated INSIDE the tank. Since this radically complicates any work to be done on either of the the two items, one is struck by 'WHY?'

    All the other bikes I am familiar with have had the fuel pump and fuel filter in an easily accessed location on the bike, enabling simple (relatively speaking) replacement. Not so the 2002 (and presumably other 6th-Gen Viffers).

    Anyone have any knowledgeable insights into the engineering logic behind this seemingly odd decision?
     
  2. dan.sideen

    dan.sideen New Member

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  3. Kalikiano

    Kalikiano New Member

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    Thanks for that reply, Dan. I guess it seems odd to me due to the fact that I've had (and worked on) carbureted bikes in the past , almost exclusively. My 2002 Viffer is my first FI bike. Appreciate the help! Cheers, K2
     
  4. Diving Pete

    Diving Pete Member

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    The filter inside the tank is very common on my carb bikes from the 80's and 90's. Putting the fuel pump in the tank solves the problem of having to suck the fuel to the pump. Also it very rarely goes wrong.
     
  5. Kalikiano

    Kalikiano New Member

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    Thanks. Every insight is helpful, DP!
     
  6. RllwJoe

    RllwJoe Member

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    As Dan mentioned above, placing the pump inside the tank provides cooling for the pump. This is a prime (pardon the pun) reason why you should not continually run the machine on an almost empty fuel tank especially when the ambent temps are hot, if it be your VFR or your automobile.
     
  7. skimad4x4

    skimad4x4 "Official" VFRWorld Greeter

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    Same location is used by most recent Triumph models. From a manufacturing perspective the fuel tank, pump and filter becomes a sub-assembly which can just be slotted in as a pre-assembled unit. If this saves a few minutes on every motorbike heading down a production line it all mounts up to $millions...

    I suspect that is probably the main reason why.
     
  8. raYzerman

    raYzerman Insider

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    The risk is very low these days. As long as there is enough fuel to pump, it will be adequately cooled. Fuel is drawn through the filter and the pump body until it gets to the business end, the gears that create the pressure. From there to the fuel rail, through the FPR and constantly recirculating via the return line. Some bikes have no return line and a relief valve built into the pump to serve as a return line internally.
    If you think about how hot a pump would have to get to fail/melt parts..... wouldn't the fuel tend to explode? Ride more, worry less.
     
  9. Kalikiano

    Kalikiano New Member

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    Yes, I guess the engineers have done their homework.. It all makes sense, now, even if removing a pump/filter becomes somewhat more of a burden that it would be otherwise. Thanks.
     
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