Forums 🚥 PIT STOP 🔧 Hyosung Technical Help [Bike Mod] GV650 & GT650 : Modification of the TOS sensor (Tip Over Sensor Mod)

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This topic contains 2 replies, has 2 voices, and was last updated by  ♠️ MARCEL 1 year ago.

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  • #1662

    • Topics: 0
    • Replies: 1
    Nov 30, 2017
    Hyosung GV 650EFI Ltd Ed
    Points: 8

    Very interesting modification, and no other like it on the net. I have problem with my gv650 efi that could  be related to the above, Bike was working perfectly, decided to do a basic service on it, Plugs, oil & filter etc, lifted the tank from where 2 bolts by the battery and used the stay to keep it up, for access to the rear plug, all good so far, had to unbolt the rad and fan etc to allow access to the front plug (stupid design) any how once done turned ignition on (while tank still lifted) to find the pump would go through its prime cycle, (as if the kill switch was on, but wasn’t) it then shortly came up with “CHE” on the dash (the only fly in the ointment to your comments should be F1 – nope) my lad came to help and I said it wont work, he sat on on the bike and turned the ignition on and yep, it primed  and started perfectly! Grrr. This took my attention to the side stand switch, duly changed and nope, same issue seems temperamental when works not work and nothing moved or change to reflect this again Grrr. Have just received a new starter solenoid/relay but my gut says this isn’t the cause as it seems a safety issue cutting power to the pump a’la your topic. Where is the TOS sensor fitted on these? can it be tested easily?  and if i was to replace it you say can use one from another manufacturer, I’m guessing connection is the same, do you know the cheapest option short of your mod? Any suggestion or thought would be appreciated as bike hasn’t been used since April and we have had the best summer since 1976!!

  • #1680

    ♠️ MARCEL
    • Topics: 32
    • Replies: 201
    Nov 30, 2017
    North UK
    Points: 2,690


    According to the manual –  The RO Switch (Roll Over) aka. (TOS Tip Over Sensor) is under the seat.
    It should be near the battery,  if you read the above ^ pdf file, you would have a visual idea of where it is.

    According to the service manual (EFI), this is what it says:

    “CHE” : The LCD panel ① indicates “CHE” letters when no communication signal from the ECU is received for 3 seconds.

    C23 = RO/TOS Switch faulty.

    For a more detailed explanation.   Download the link below and go to pages:
    #27, #34, #47, #66 ,
    – Service Manual Link –


    Personally I don’t have a TPS sensor on mine, if it did, i’d find ways to get rid of it myself.   But i have no experience in using other brand manufacture TOS sensors on a GV650

    However, the above ^ book at the top, does mention that you may use other brands from “EFi/Ei”  (injected bikes.)  Designs may also vary too.

    This is the most recent TOS sensor hyosung uses that I know dealers to be stocking up,



    Hope this info helps,  let us know how you get on!

    // Meditation doesn't mean you have to sit still....

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