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Thread: 92 k75rt fuel consumption woes ...

  1. #16
    Registered User argent brick's Avatar
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    Quote Originally Posted by lostboy View Post
    .... used the idle drop/starter button mixture check?
    What is that?
    Lynn
    MOA #57883
    Current Ride: 1995 K75 Standard
    Past: 1978 Yamaha XS 750, 1976 BMW R60/6

  2. #17
    Rally Rat
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    My bike ran fairly well for 8000 miles after I bought it last year, and I averaged about 38 mpg.

    I checked and adjusted the valves last spring and that instantly brought me up to 45+ mpg, sometimes 50 mpg with good ethanol-free fuel.

  3. #18
    3 Red Bricks
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    Quote Originally Posted by ARGENT BRICK View Post
    What is that?
    Something that is only relevant when everything else is properly adjusted (valve adjust, throttle sync, etc).

    When the bike is fully warmed up and running, pressing the starter button should not cause the idle to rise (if it does, the bike is running lean). Inserting the altitude plug should not cause the idle to rise (if it does, the bike is running too rich). Ideally, both these tests should cause the idle to drop slightly.

    ONLY APPLICABLE IF EVERYTHING ELSE IS ADJUSTED CORRECTLY AND NO VACUUM LEAKS!!!



    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

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

  4. #19
    Registered User argent brick's Avatar
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    Well it is clear, Lee, that I need to get my bike to you, so that I can learn about it.

    What would novice brick owners do without you?
    Lynn
    MOA #57883
    Current Ride: 1995 K75 Standard
    Past: 1978 Yamaha XS 750, 1976 BMW R60/6

  5. #20
    Registered User scoobs's Avatar
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    Thumbs down Still no good.....

    I replaced the "Z breather hose" as suggested somewhere on here but no improvement
    I've contacted a couple of local (150 miles away) repair shops but they claim their diagnostic equipment is too modern to use on my bike.
    HELP!!!
    Ian.
    Ian Robert "Scoobs" Scobie

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

  6. #21
    3 Red Bricks
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    What was the result of your valve adjustment check?



    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

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

  7. #22
    Registered User scoobs's Avatar
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    To be honest I haven't checked the valves- I'm scared I make things worse... Is this a reasonably failsafe task?
    Cheers for sticking with me on this issue,
    Ian.
    Ian Robert "Scoobs" Scobie

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

  8. #23
    3 Red Bricks
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    Ian,

    CHECKING the valves only involves removing the valve cover and being able to operate feeler gages. The only thing you can make worse doing this is: a leaky valve cover gasket because you didn't replace the 10 $.73 grommets that go on the valve cover bolts or stripped out threads on the head because you torqued the valve cover bolts more than 6 1/2 ft/lb (78 in/lb) Always use an INCH/lb torque wrench for these bolts as a FOOT/lb torque wrench is not accurate at such low torque ($20 from Harbor Freight $9.99 on sale). Engine must be cold (less than 90 degrees) not ridden for the previous several hours.

    ADJUSTING the valves IF any are found to be out of tolerance requires $30 worth of special tools. The actual adjusting can be done at a later date once you know that there is one (or more that need adjusting). This allows you to order the tools and set aside time to do the job when convenient.

    Follow your manuals instructions.

    Valve checking/adjusting is something that should be done at least every 15,000 miles. The more miles that are on the bike, the higher the odds of the valves needing adjustment. If you don't stay on top of it, it can cause all kinds of problems.


    PM me with your phone # if you want me to talk you through it and tell you my "easy" method.


    Last edited by 98lee; 01-28-2013 at 07:40 PM.
    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

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

  9. #24
    Registered User
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    K100RS Poor MPG fixed

    I did a trip with low mileage. When I got back my K bike rec'd afuel filter and then a fuel pressure regulator. Old one had not worked correctly, pressure too high.
    Next I changed the temp sensor, went well with a sawed off (short) 19 mm open end wrench. These things might have helped but then found (myself) some tight valves, esp exhaust. Had them adjusted (by a dealer) and mileage went back up over 40. Your K75 should respond similarly.

  10. #25
    K75RT Keith
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    Poor mileage isn't just related to the engine. Bad wheel bearings, rubbing brake pads or a failing bearing in the drive line can all reduce mileage. Might be worth looking.

  11. #26
    A bozo on the bus deilenberger's Avatar
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    One other thought to leave you with..

    Winter mileage is typically poor. The L-Jetronic system uses an intake temperature sensor to richen the mixture when there is cold air. It actually tends to run a bit too rich IMHO even on a correctly adjusted/working bike. Since there is no feedback (02 sensor) in the system, it has no way to correct for the rich mixture. The use of a simple air-flow-meter instead of a MASS-air-flow (MAF) meter compounds the problem. The system doesn't know the density of the air, so the fuel map is purposely biased toward rich as the temperature drops to avoid running the engine lean.

    The nice part of this is - how great the engine feels with cold dense air and a rich mixture. The bad part can be the fuel mileage suffers. The winter-mix gasolines also tend to do this to some extent.

    Really a case of YMMV - but on a K75, if it's running good, and the temperatures are below about 45F, IMHO, 35-38MPG is about normal. At least it was on mine.
    Don Eilenberger http://www.eilenberger.net
    Spring Lk Heights NJ NJ Shore BMW Riders New Sweden BMW Riders
    '07 R1200R (current ride) and some bimmers.. and a Porsche

  12. #27
    Registered User scoobs's Avatar
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    thanks

    Forgive my delay in replying, I've been having computer issues as well
    Thanks for the on-going advice- I'll let you know how the valve clearance check goes.
    Cheers,
    Ian
    Ian Robert "Scoobs" Scobie

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

  13. #28
    Registered User scoobs's Avatar
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    Thumbs down update..

    checked the valve clearances today and they were okay, also balanced the throttle bodies and installed another set of spark plugs.
    Still no change in MPG so I'm now looking at rear crown bearings- anyone have any experience of problems here, as there are two different bearings and I don't want to replace both if not needed.
    The brake pads don't appear to be rubbing, wondering if an out of adjustment clutch might be a factor in this ongoing equation??
    Thanks to all for your continuing input.
    Cheers,
    Ian.
    Ian Robert "Scoobs" Scobie

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

  14. #29
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    k75 fuel consumption

    Quote Originally Posted by jpevehouse View Post
    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 had fuel consumption problems.Replaced most everything replaceable finall did compression check on advice of a auto mechanic.BIKE HAD POOR COMPRESSION REMIDY i REPLACED ENGINE FROM beemer bONE YARD.hARD FIX but problem solved.
    Rod
    62342

  15. #30
    3 Red Bricks
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    It's possible that the fuel injectors need cleaning/servicing.

    Mr.Injector in Idaho can service yours or sell you some replacement ones at a VERY reasonable price.

    http://www.mrinjector.us/



    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

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

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