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Thread: 92 k75rt fuel consumption woes ...

  1. #1
    Registered User scoobs's Avatar
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    Question 92 k75rt fuel consumption woes ...

    My K75 has 120,000 miles on it and I've noticed that my fuel consumption has deteriorated quite dramatically. I used to get 220 miles per tank (50 MPG) but this has dwindled to a miserable 160 miles (35 MPG). I'm aware that the use of ethanol in the gas has an adverse affect on MPG but surely not this much?
    I've installed a new air filter and spark plugs but this hasn't made any obvious improvement so would be thrilled at any helpful suggestions. I recall reading somewhere of a faulty sensor that can cause excess fuel to be injected into one of the cylinders but am unable to locate said article.
    I average 15,000 miles a year and so any improvement will save me a decent amount of money.
    Cheers,
    Ian.
    Ian Robert "Scoobs" Scobie

    '92 K75RT, '02 F650GS Dakar;
    But fondly miss.. R80RT, R45,CB250RS,DT125MX,TS100

  2. #2
    MichiganMike MICHIGANMIKE's Avatar
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    K75 Fuel Mileage

    I filled up my 94Standard today and got 51 mpg, best since I bought this bike with 15K on it. Currently has 53K. I use fuel injector cleaner about three times a year and this year have 20K on the bike. I notice that fuel mileage varies a lot with the blended fuels we get today and also on the riding. When I run the freeway with either of my K75s the mileage will drop down to closer to 42/43MPG. With your mileage you might want to run some injector cleaner in there for three or four tanks in a row and see if that helps. I don't remember ever seeing an article as you mentioned in your post. If you find it or someone else does, please share that info.

  3. #3
    3 Red Bricks
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    A bad water temp sensor can cause the bike to run richer.

    http://ibmwr.org/ktech/gas-mileage.shtml


    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

    Lee Fulton Forum Moderator
    3 Marakesh Red K75Ss
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  4. #4
    K75RT Keith
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    Fuel Consumption Issues.

    With 120K on the clock the injectors may need cleaning (professional).

    My 90 K75Rt went from 40 to 55mpg after sending the injectors out to Mr. Injector.

  5. #5
    Registered User scoobs's Avatar
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    Exclamation

    Holy Cr@p!!!! sorry but I had issues with the sensor wiring three years ago when a mouse nested near my airbox while I was out of the country- I just taped it up and forgot about it as I had no obvious temperature control issues at the time. I've ridden +50k miles since then, goodness knows how much gas I've wasted
    Just put the ohm meter across terminal #10/ground and getting 2322 ohms with an ambient temperature of 71*F, which is close to the 2.5kohms listed on the trouble shooting link, so I don't appear to have an open circuit or direct short in the wiring. I'll test it again in the morning as the temereature is supposed to drop to around 45*F, then will run the engine until the fan kicks on as also suggested and recheck the resistance. I assume I'll have to reconnect the FI computer in order to run the bike, then disconnect again to take the readings?
    I'll also investigate local options for getting the injectors cleaned, although I do run "Seafoam' through the tank before my regular oil changes.
    Thanks to Y'all for your help, if anyone has any further suggestions please feel free to comment.
    Cheers,
    Ian
    Ian Robert "Scoobs" Scobie

    '92 K75RT, '02 F650GS Dakar;
    But fondly miss.. R80RT, R45,CB250RS,DT125MX,TS100

  6. #6
    Pevey jpevehouse's Avatar
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    Glad yours was so easy to fix. I've been battling poor mileage on mine since I got it. Normally around 35 mpg but on highways with moderate speed, I can get 39 or so.
    Replaced temp sensor - to get the fan working, intake rubber, new injectors, lots of gas treatment, balanced TB, checked and adjusted valves, new plugs and went over every thread on several forums regarding bad mileage. Pretty sure the brakes are not dragging. It has always started and run like a sewing machine.

    Let me know how yours turns out.
    I must go down to the seas again, to the lonely sea and the sky,
    And all I ask is a tall ship and a star to steer her by,


    James and his 1988 K100LT

  7. #7
    Registered User scoobs's Avatar
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    Arrow Update

    Okay, so the temperature sensor ohmed out correctly at various points on the scale- so it is working properly in spite of the sterling efforts of the local mice
    I've pulled the fuel injectors (haven't seen any before but they looked dirty) and shipped them off to "Mr.Injector" as suggested.
    I'll give further updates when I get them back in the bike and do a test run.
    Thanks to all who've given advice on this matter.
    Ian.
    Ian Robert "Scoobs" Scobie

    '92 K75RT, '02 F650GS Dakar;
    But fondly miss.. R80RT, R45,CB250RS,DT125MX,TS100

  8. #8
    Registered User scoobs's Avatar
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    Exclamation Help!!!

    Okay, got my injectors back from "Mr.Injector"- reasonable turnaround time and well packaged !!
    I refitted them to the fuel rail and installed in the bike, but it will not fire up
    I remembered to reconnect the tank plug and the hook ups to the injectors, the fuel pump runs and I've got pressurised fuel at the rail- anyone got any thoughts as I'm hoping to take the bike to Florida on Thursday.
    Thanks,
    Ian.
    Ian Robert "Scoobs" Scobie

    '92 K75RT, '02 F650GS Dakar;
    But fondly miss.. R80RT, R45,CB250RS,DT125MX,TS100

  9. #9
    3 Red Bricks
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    Check the main plug to the EFI computer. Make sure that it is properly seated.

    Do you have spark? Pull a plug and ground it to the engine. Crank the engine to see if you have spark.



    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

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

  10. #10
    Registered User scoobs's Avatar
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    Lightbulb

    Strangely enough, I thought about the FI computer hook up after I got to work so will check the connector in the morning. That sounds like the problem as I had disconnected it when verifying the output resistance from the temperature sensor and may not have got a good connection when I reassembled everything.
    I do have power to the spark plugs as I got a blue flame when trying to crank it with the injectors pulled- probably a good thing the injectors didn't work or I might have set the garage on fire !!
    Maybe I'll get to Florida after all, I'll post an update tomorrow.
    Cheers,
    Ian.
    Ian Robert "Scoobs" Scobie

    '92 K75RT, '02 F650GS Dakar;
    But fondly miss.. R80RT, R45,CB250RS,DT125MX,TS100

  11. #11
    Registered User scoobs's Avatar
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    Thumbs up Duh!!

    Okay, so I connected the FI computer and the bike fired up- I'll report on any MPG changes when I get back from Florida
    Ian
    Ian Robert "Scoobs" Scobie

    '92 K75RT, '02 F650GS Dakar;
    But fondly miss.. R80RT, R45,CB250RS,DT125MX,TS100

  12. #12
    3 Red Bricks
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    When connecting the plug to the computer, always put one hand on the rear of the computer (you must remove the right battery cover) . Since the computer is rubber mounted, just pushing from the front can allow the computer to flex in its mounts and not always allow the plug to properly seat. You MUST hear a distinct click as the connector locks into place. Failure to properly seat the connector MAY allow the bike to run, but will eventually cause all kinds of problems due to poor connections.



    Last edited by 98lee; 01-28-2013 at 12:55 AM. Reason: sp.
    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

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

  13. #13
    K75RT Keith
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    What did the report on the injectors show prior to cleaning?

    You may also want to check if your brakes are dragging
    Also, When was the last time you greased/replaced the wheel bearings?

  14. #14
    Registered User scoobs's Avatar
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    Thumbs down Back to the drawing board....

    Well I gave the bike a good run this past weekend- 1000 miles round trip for the "Sun your buns" rally. Sadly the gas return remains the same at around 35 MPG, so while cleaning the injectors was probably necessary it hasn't solved my problem.
    Any suggestions welcome,
    Ian
    Ian Robert "Scoobs" Scobie

    '92 K75RT, '02 F650GS Dakar;
    But fondly miss.. R80RT, R45,CB250RS,DT125MX,TS100

  15. #15
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    Have you ever put the bike on an exhaust gas analyser, or if one is unavailable, used the idle drop/starter button mixture check?

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