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Thread: Starting issue has me stumped

  1. #1
    Tom Mieczkowski mieczkow's Avatar
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    Starting issue has me stumped

    I have a 1987 K75S and ten years of mostly trouble free history. Over the years I have done all the routine maintenance myself. I have a well equipped shop as I also restore old Lotus Cars. I have run into a problem which has me stumped and after two days of working on it I am more or less where I started. Hoping someone can suggest some next steps to take.

    I drove the K75 to my shop and shut it down. I was doing a little cosmetic clean-up on it. When I went to restart it it would not crank. Having been through this before I removed the tank, tapped the starter relay and it started up. That relay was replaced about five or six years ago. I decided to order one and replace it. I ordered one from Texas Industrial and it arrived. When I installed the new relay I had "runaway starter syndrome". The relay had clamped closed. I disconnected the battery to shut the bike down.

    I had a pretty small Westco battery in the bike and it was about six years old. I decided that the battery might be contributing to the relay seize so I bought a full size aftermarket battery which fit the bike like a glove. Tried starting it and had the starter run away again. Shut it down and put in the old relay. Bike would crank but wouldn't start.

    Started checking things. Fuel pump runs, tank is super clean, fuel is good. Put a fuel pressure gauge on it and have 38 psi after the fuel rail. Checked the fuel pressure regulator, found a break in the vacuum line and replaced the line with a new one.

    Went to start the bike. It was a little balky but it did fire up and ran normally. No smoke, good throttle response, sounded just like normal. Shut it down. Went to restart it a little later, would not start. Continued to crank it but the starter would at times crank robustly and at times weakly. Finally stopped cranking.

    Put a charger (trickle) and left it overnight. Next morning started up, but same as before. A little balky and then it caught and ran normally. Shut it down. Went to restart and it would crank but not start. Checked plugs, put in new ones and all the plugs are getting spark. Plugs are also fuel wet when I Inspected them.

    If I jump the starter relay it cranks like the devil, much more robust than going through the relay. Sounds like the starter is very healthy (it was replaced about five years ago) and the battery seem to have plenty of power.mLights are bright, etc. charger indicates battery is good.

    Went through the same scenario today. Checked everything again, fuel pressure, spark, plugs, etc. cranked it and it started. Shut it down and then back to square one, would not start but will crank. However cranking via the relay still seems weak/slow compared to jumping the relay and going directly to the starter motor. Can the drop-out relay be a problem here? I've tested the relays on the bench and they all activate when 12V is applied.

    Boy after two days of this I've run out of ideas and starting to lose my sense of rational thinking about how to diagnose this. Can somebody slap me upside the head and point me in the right direction. I have a sense this is electrical, relay involved but I'm not at all sure what I should do next.
    Tom Mieczkowski
    1987 K75S

  2. #2
    Registered User mlytle's Avatar
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    when was the last time you cleaned all the electrical ground connections? (under tank on frame, below battery on frame, starter, etc, and the major other connectors?
    Marshall
    92 K75s, 94 K75s, 96 K1100RS (caretaker), 09 K1300s

  3. #3
    Quote Originally Posted by mieczkow View Post
    I have a 1987 K75S and ten years of mostly trouble free history. Over the years I have done all the routine maintenance myself. I have a well equipped shop as I also restore old Lotus Cars. I have run into a problem which has me stumped and after two days of working on it I am more or less where I started. Hoping someone can suggest some next steps to take.

    I drove the K75 to my shop and shut it down. I was doing a little cosmetic clean-up on it. When I went to restart it it would not crank. Having been through this before I removed the tank, tapped the starter relay and it started up. That relay was replaced about five or six years ago. I decided to order one and replace it. I ordered one from Texas Industrial and it arrived. When I installed the new relay I had "runaway starter syndrome". The relay had clamped closed. I disconnected the battery to shut the bike down.

    I had a pretty small Westco battery in the bike and it was about six years old. I decided that the battery might be contributing to the relay seize so I bought a full size aftermarket battery which fit the bike like a glove. Tried starting it and had the starter run away again. Shut it down and put in the old relay. Bike would crank but wouldn't start.

    Started checking things. Fuel pump runs, tank is super clean, fuel is good. Put a fuel pressure gauge on it and have 38 psi after the fuel rail. Checked the fuel pressure regulator, found a break in the vacuum line and replaced the line with a new one.

    Went to start the bike. It was a little balky but it did fire up and ran normally. No smoke, good throttle response, sounded just like normal. Shut it down. Went to restart it a little later, would not start. Continued to crank it but the starter would at times crank robustly and at times weakly. Finally stopped cranking.

    Put a charger (trickle) and left it overnight. Next morning started up, but same as before. A little balky and then it caught and ran normally. Shut it down. Went to restart and it would crank but not start. Checked plugs, put in new ones and all the plugs are getting spark. Plugs are also fuel wet when I Inspected them.

    If I jump the starter relay it cranks like the devil, much more robust than going through the relay. Sounds like the starter is very healthy (it was replaced about five years ago) and the battery seem to have plenty of power.mLights are bright, etc. charger indicates battery is good.

    Went through the same scenario today. Checked everything again, fuel pressure, spark, plugs, etc. cranked it and it started. Shut it down and then back to square one, would not start but will crank. However cranking via the relay still seems weak/slow compared to jumping the relay and going directly to the starter motor. Can the drop-out relay be a problem here? I've tested the relays on the bench and they all activate when 12V is applied.

    Boy after two days of this I've run out of ideas and starting to lose my sense of rational thinking about how to diagnose this. Can somebody slap me upside the head and point me in the right direction. I have a sense this is electrical, relay involved but I'm not at all sure what I should do next.
    I don'y much much about this specific bike model but if it were a car I'd check, clean and reseat all the relays and fuses. Relays can cause this kind of mayhem but I don't know if your bike even has relays. Ignition switches can cause all kind of oddities too. Even if the switch is good the connections may be weak, corroded or shorting. I HATE problems like this! Good luck with it. BTW the suggestion on checking the grounds is a fantastic suggestion and maybe indeed ought to be checked first.

  4. #4
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    A quick test when it is not starting:
    Key and kill switch on but don't push the starter button, check the voltage on the back of the top fuse. Put one probe in one of the two little holes in the back of the fuse and the other probe on the bolt above the shift lever where the battery ground connects to the transmission.

    If the voltage is less than 11.5 volts (and the voltage of your battery across the battery terminals is above 12.3) you probably have dirty conntacts inside your ignition switch or kill switch. They are cleanable. If that is your problem, I'll get you the instructions.



    Last edited by 98lee; 01-15-2016 at 03:15 AM.
    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

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

  5. #5
    Tom Mieczkowski mieczkow's Avatar
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    Thanks for the suggestions. I did check the ground on the frame, low on the left side but not under the tank. That's a great suggestion. Can you point me to where that under the tank ground is?

    Overall the bike is quite clean and over the dare I have owned it I replaced the switch assemblies on both the righ and left side. And definitely agree intermittent electrical problems are a real pain 😩
    Tom Mieczkowski
    1987 K75S

  6. #6
    Registered User mlytle's Avatar
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    left side of center frame tube, about 6 inches back from the forward tank mounts. there are 5 or so wires that are all on same 10mm bolt.
    Marshall
    92 K75s, 94 K75s, 96 K1100RS (caretaker), 09 K1300s

  7. #7
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    Quote Originally Posted by mlytle View Post
    left side of center frame tube, about 6 inches back from the forward tank mounts. there are 5 or so wires that are all on same 10mm bolt.
    They are all brown wires.

    Check the voltage at the fuse first. It's the quickest and easiest test you can do.


    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

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

  8. #8
    Not that you care right now but looking at your photo bucket pics...that's a beautiful bike! Just fantastic looking!

  9. #9
    Tom Mieczkowski mieczkow's Avatar
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    Thanks again for the help. I'll report back on what I find.
    Tom Mieczkowski
    1987 K75S

  10. #10
    Tom Mieczkowski mieczkow's Avatar
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    Quote Originally Posted by 98lee View Post
    A quick test when it is not starting:
    Key and kill switch on but don't push the starter button, check the voltage on the back of the top fuse. Put one probe in one of the two little holes in the back of the fuse and the other probe on the bolt above the shift lever where the battery ground connects to the transmission.

    If the voltage is less than 11.5 volts (and the voltage of your battery across the battery terminals is above 12.3) you probably have dirty conntacts inside your ignition switch or kill switch. They are cleanable. If that is your problem, I'll get you the instructions.



    Lee,

    Bingo! Battery voltage 12.9, voltage at the fuse terminal 10.3. Can you forward those instructions to me?

    Tom
    Tom Mieczkowski
    1987 K75S

  11. #11
    3 Red Bricks
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    Tom,


    Clean the kill switch contacts FIRST as these are very quick and simple to do and who knows, you may get lucky and that will fix the problem.

    To clean the kill switch contacts:

    Remove phillips screw that holds right hand switch assembly to throttle perch. It's at the very bottom front, to the left of the turn signal switch. Slightly lift and pull away, disengaging the tab at the top.

    Rotate switch assembly so that kill switch is facing down.
    Remove E clip from rear of kill switch lever and carefully lower kill switch lever away from assembly. There are two very small springs and a contact plate that should come out on the lever. Don't turn it over or they will fall off! Take lever to a clear bench area to remove and clean contact plate and springs.

    Clean contacts inside switch assembly.

    Reassemble.

    Retest voltage drop at fuse #1. If still an issue, continue with instructions below on how to disassemble and clean ignition switch.



    http://ibmwr.org/ktech/clean-ignition-switch.shtml

    http://ibmwr.org/ktech/ign-switch-disassemble.shtml




    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

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

  12. #12
    Tom Mieczkowski mieczkow's Avatar
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    Quote Originally Posted by 98lee View Post
    Tom,


    Clean the kill switch contacts FIRST as these are very quick and simple to do and who knows, you may get lucky and that will fix the problem.

    To clean the kill switch contacts:

    Remove phillips screw that holds right hand switch assembly to throttle perch. It's at the very bottom front, to the left of the turn signal switch. Slightly lift and pull away, disengaging the tab at the top.

    Rotate switch assembly so that kill switch is facing down.
    Remove E clip from rear of kill switch lever and carefully lower kill switch lever away from assembly. There are two very small springs and a contact plate that should come out on the lever. Don't turn it over or they will fall off! Take lever to a clear bench area to remove and clean contact plate and springs.

    Clean contacts inside switch assembly.

    Reassemble.

    Retest voltage drop at fuse #1. If still an issue, continue with instructions below on how to disassemble and clean ignition switch.



    http://ibmwr.org/ktech/clean-ignition-switch.shtml

    http://ibmwr.org/ktech/ign-switch-disassemble.shtml




    Thanks Lee. I'm on the road for the next week leaving tomorrow so I won't get to this until I return, but I'll let you know how it works out.
    Tom Mieczkowski
    1987 K75S

  13. #13
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    Quote Originally Posted by mieczkow View Post
    Lee,

    Bingo! Battery voltage 12.9, voltage at the fuse terminal 10.3. Can you forward those instructions to me?

    Tom
    Tom,

    Make sure the 12.9 battery voltage is also with the key and kill switch on.




    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

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

  14. #14
    Tom Mieczkowski mieczkow's Avatar
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    Cleaned both the start button and the key/light switch assembly. The bike now cranks consistently but is still not starting properly. I did get it started once this afternoon and once started it runs properly. But once it is shut down it would not start again. Spark was rechecked and is good. Lots of fuel, perhaps too much - this might be the issue.

    I'll keep at it tomorrow.
    Tom Mieczkowski
    1987 K75S

  15. #15
    Fortis Fortuna Adiuvat Omega Man's Avatar
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    Quote Originally Posted by mieczkow View Post
    Cleaned both the start button and the key/light switch assembly. The bike now cranks consistently but is still not starting properly. I did get it started once this afternoon and once started it runs properly. But once it is shut down it would not start again. Spark was rechecked and is good. Lots of fuel, perhaps too much - this might be the issue.

    I'll keep at it tomorrow.
    Progress
    OM
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