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Thread: k 75 won't start

  1. #1

    k 75 won't start

    bike has been sitting for about a month since it got cold. started it once during this time but now it won't start. checked and cleaned the plugs but still no success. Any ideas would be helpful

  2. #2
    Focused kbasa's Avatar
    Join Date
    Mar 2003
    Marin By God County, California
    Where are you Jay?

    Does it crank?
    What did you find on the plugs?

    I had a couple K75s and they were very reluctant starters in cold weather. I usually wound up putting fresh plugs in it to get it started. My Kbike would invariably foul the plugs, so I wound up starting it without the choke. Once it started to fire, I'd switch the choke on.
    Dave Swider
    Marin County, CA

    Some bikes. Some with motors, some without.

  3. #3
    when I pulled the plugs they had some carbon buildup. The bike cranks very well. It seems like it wants to start some sputtering but nothing more. Bike had a full tune in august and has always started on first try every time. Only thing different is that I put it on the centerstand which I don;t normally do but thought it would be better for extended downtime. Thanks for the reply. john

  4. #4
    rabid reader dbrick's Avatar
    Join Date
    Apr 2003
    Santa Cruz CA

    Let's approach this systematically. The bike needs air, spark, and fuel to run. We can assume (!) it's getting air...unless some little creature has taken up residence in the air intake and blocked it.

    1. Check for spark. One at a time, pull the spark plugs, and while grounding its theads against the valve cover, turn the ignition switch on and press the starter button. Can you see a spark across the spark plug contacts?
    If you can, you've got ignition. Make sure the plug gap is correct, and reinstall it.
    If there's no spark, then you've got an ignition problem. You'll need to check the primary wiring to coil, the HT lines to the plugs, and the hall effect sensor on the motor.

    2. Check for fuel delivery. Fuel is delivered to the cylinders by three fuel injectors, which are fed from the fuel rail. You can remove the two (I think) 10mm bolts, and pull the whole fuel rail off the side of the motor. Be careful not the push the dirt around the fuel injector snouts into the intake manifold. With the rail off the motor, and pointed into a bucket, turn on the ignition and touch the starter button. You should see a nice, uniform spray from each of three injectors. WARNING: SPRAYING GAS IS EXTREMELEY FLAMMABLE. This is best done outdoors.
    If you've got spray, then you have fuel delivery.
    If not, you need to find out why. The most likely culprits are electrical connections to the fuel pump. It is possible as well that the fuel pump has failed, or the fuel filter has clogged or split, or the injectors are clogged.

    (While not expected, I once had a K fail to start even with spark and fuel delivery. It turned out that the bike had been run to empty, then refueled with water!)

    I've had various Ks for years. They are, indeed, sensitive to flooding. Removing and drying the plug, and making sure the combustion chamber is dry too, may solve the problem. (If the combustion chamber is coated with fuel from unsuccessful start attempts, the mixture in there may be too rich to ignite.) You can dry the chamber by: removing the spark plugs, and grounding them to the valve cover. Disconnect the electrical connections to the three fuel injectors, so they don't spray. Then operate the starter, which will pump air through the motor and help it to dry.

    One of these oughta work; Ks are known for running essentially immediately when the starter button is pushed. Good luck!
    David Brick
    Santa Cruz CA
    2007 R1200R

  5. #5
    Rally Rat colt03's Avatar
    Join Date
    Mar 2003
    South Windsor, CT
    An old trick we use when snowmobileing is to take out the plugs, set them on top of the woodstove until they warm up, almost to hot to hold and them put them back in your bike. I didn't see where you are from so if you don't have a woodstove throwing off some heat, You can use a heat gun or hairdryer .

    Good Luck

    Craig Cleasby
    South Windsor, CT
    1996 K1100LT
    2004 R1150GS
    Yankee Beemers

  6. #6

    Unhappy plug fouling

    Observations after a few K machines:
    1> intake side is up, guides allow oil into intake area, injector sprays gas (aka oil dilution solvent), oily cloud fouls plugs.
    2> for the serious, get a plug sandblaster & keep several sets clean as spares. After 1 change, I use finger tightness until the engine behaves itself to avoid stressing head threads. As soon as it idles smooth, tighten properly.
    3> I had one that usually took 3-4 clean sets to come around after winter (3-4 mo).
    4> I think it's random combination of valve/guide positions that K engines sometimes startup in a blue cloud. It'd better go away in ~30 sec.
    5> If it starts up crisp & clean after winter, it's a beautiful thing.

  7. #7

    Thumbs up oops, 1 more

    Colt03 has it right on. Getting the plugs as hot as you can deal with also goes back to the early 2 stroke days as well, for the same reasons. I've used a propane torch (well away from it all) to heat/burn clean before.

  8. #8
    Sometimes when a K75 is washed and parked for a few weeks or started and shut down and parked, they don't want to start. Having a full charge on the battery and a new set of plugs usually gets it going after numerous tries. You don't want to try to start it if the battery is low, or bad things happen to the starter relay.
    Frank G.
    Hattiesburg, Mississippi
    2004 R1150RT

  9. #9
    I have tested the firing and I am getting spark on all plugs. when I pulled the plugs they were wet with fuel so I think that would indicate fuel flow.I will replace with new set of plugs and see how that goes. Thanks for all the replies.

  10. #10
    new set of plugs and it fired right up great advice thanks

  11. #11
    What's that noise...? basketcase's Avatar
    Join Date
    Mar 2003
    Glad to know it started. I was sitting around interested in this one, because all my K's have always started with no problem -- wet or dry, summer or winter.

    Something I thought of is the condition of the fuel. "Has the gas gone bad?" "Did he use a gas stabilizer?" When winter arrives, I usually dump the appropriate amount of Stabil in my tanks to offset the gummed up issues of deceased gas.

    Additionally, as noted by several others, I too have observed a pronounced tendency for my K's to emit ("belch," is perhaps more accurate) a cloud of blue smoke when started after being parked on the side stand for a week or so. And the tendency is alliviated somewhat by use of the center stand.

    So, you might want to park your nicely running K on the center stand as an angle on avoiding a repeat of the won't start adventure. Maybe it will help.
    '98 BMW Z3 Roadster, '00 R1100RT

    If you insist on exercising a right to burn our flag, first be so kind as to wrap yourself in it and then douse yourself with gasoline just before you strike the match.

  12. #12
    Registered User BOBINILLINOIS's Avatar
    Join Date
    Jan 2004
    Champaign, Illinois
    I have had the same problem with my 1994 K75. When the weather got very cold I ran the battery down while trying unsuccessfully to start the bike. A friend told me that what worked for him was to do the following:

    1- Make sure the battery was fully charged using a Battery Tender.

    2- Start the bike with no choke and the throttle held fully open.

    3- The bike will sputter a little but it should quickly start. When it does you have to reduce the amount of throttle but not enough to kill it.

    4- Let it run at high revs for at least a minute or two to make sure the plugs are firing normally.

    I have done this a couple of times this winter and it worked just as he said it would. In my case during step 4 (after the engine was running for a few minutes with the throttle held partially open) I opened the choke half way while it was running and then was able to release the throttle. At that point it would idle normally until the engine was warm and I could ride.

    Not sure that this is the best method, but it worked without having to remove the plugs.


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