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Thread: K75C no start after restoration !

  1. #1

    K75C no start after restoration !

    This was supposed to be the greatest moment of the restoration, this first startup.

    4 months of due work, all documented with numerous photos.

    Battery charged, key ON... NOTHING, I mean NOTHING !

    Been looking in the Clymer, When the key is on, all four contacts of the switch must be continuons between each other.

    Not the case here, they are continuons 2 by 2.

    So I unplugged the ignition switch and linked the 4 contacts and sure enough, the dash lit, the relays cliked and the engine was ready to turn. But no gas tank.

    I removed the ignition switch, dismantled it and sure enough everything was perfect inside.

    I checked the kill switch, everything fine on this too.

    What am I missing ?

    The K75C was a frame off, but with numerous pictures and markings, all the wires are plugged correctly, at least I think !

    Any help Will be appreciated, been on that for a couple of jours now...

  2. #2

    Just been reading that the ignition switch is OK, with the 2 contacts on one side and the 2 other contacts on the other.

    The weird part ? Joining the 4 contacts is like putting the ignition key ON and everything is ok...

  3. #3
    Well, I Found the culprit... Broken wire on the ignition switch connexion.

    Repaires, now I have ignition and starter 🙂.

    I have to get some more gas and I will try it !

    It wasn't obvious... See the picture!PXL_20220508_175041057.jpgPXL_20220508_170507645.jpgPXL_20220508_172446958.jpg

  4. #4
    Fortis Fortuna Adiuvat Omega Man's Avatar
    Join Date
    Jan 2010
    Nice work.
    "You can do good or you can do well. Sooner or later they make you choose." MI5
    Mod Squad
    2009 F800GS 1994 TW200

  5. #5
    Thanks !

    Now it cranks, I have Spark, but no fuel...

    Anyone ?


  6. #6
    3 Red Bricks
    Join Date
    Jan 2007
    Pleasanton, Ca.

    If you tap the starter button, can you hear the fuel pump run for a second or two after?


    Ride Safe, Ride Far, Ride Often

    Lee Fulton Forum Moderator
    3 Marakesh Red K75Ss
    Mine, Hers, Spare

  7. #7
    Yes Lee,

    The pump is working for a second or two after I stop pushing on the starter button.

    I didn't alter any of the injection parts in the restoration.

    One weird thing is when a first try to start it, the right flasher wasn't working, and putting the right flasher on, the gas pump was starting !!!. I cleaned th contact of the flasher, it started working correctly, and the pump wasn't working anymore when the flasher was on. Flasher flashes ok now.

    All lights are ok, gear position sensor ok, dash light ok.

    The no gas is verified, by removing the plugs and absolutely no gas smell and clean dry new plugs...

    Is the fact that the bike didn't start in the last 6 months has something to do ?


  8. #8
    #13338 PGlaves's Avatar
    Join Date
    Oct 2003
    "Big Bend" TX
    When one circuit effects a totally different circuit it often screams bad ground. Lacking a good ground electrons find other more nefarious ways to flow.
    Paul Glaves - "Big Bend", Texas U.S.A
    "The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russell

  9. #9
    Thanks Paul I'll have a look at the grounds !

  10. #10

    Problem solved !

    After all the readings and thinking I was going to swap the airflow meter for a known good one, since all indications pointed to a faulty air temperature sending device.

    Doing so, I discoverded an unplugged 4 prong connector, right over the air box, well hidden. checked the color of the wires, and sure enough the was that Green/Red stripe one that feed the 12 volts to the injectors.

    I plugged the connector and... Vroum !

    It's been an interresting endeavour to discover that, one that taught me all about the (quite simple) injection system of the K75.

    Thanks all for your input, this forum is invaluable !


  11. #11
    Registered User 6322's Avatar
    Join Date
    Mar 2012
    Riggins, ID
    Thanks for your followup! It helps us all to learn a little more.
    Gary Phillips - #6322
    Wildland Firefighter, Retired, Riggins, ID
    Heartland Moto Locos BMW Riders
    '77 R100/7 Dirt Hack, '83 R80ST, '85 K100RS w/EML, '93 K1100LT, '00 R1100RS

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