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Whirring noise left side 1982 XJ550

Discussion in 'XJ Technical Chat' started by SawyerH, Aug 12, 2020.

  1. SawyerH

    SawyerH New Member

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    I recently rebuilt the carbs in my 550 because one the of the floats was sticking. I changed the oil because I noticed some gas smell in the oil. I changed it once then I changed it again with a new filter. Ever since I changed the oil there is a loud whirring sound that comes from the left side of the motor. Speed/gear/clutch position don't seem to affect it but it does go away when I accelerate and when I am driving. It starts again when I slow down. I'm running 20w50 motorcycle oil. Any idea what the sound could be?
     
  2. Timbox

    Timbox Well-Known Member

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  3. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    The 550 has a hydraulic primary chain tensioner. At idle the tensioner is slightly slack due to the lower oil pressure.
    It's normal, and causes no harm.
    To be sure that's the issue raise the idle to 1500 RPM and see if it gets quieter.
     
  4. SawyerH

    SawyerH New Member

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    [QUOTE="Timbox, post: 647726,

    Did you run your bike with the gas in the oil for a long time? I always use the above oil in all my XJ bikes. Good luck.[/QUOTE]

    It may have been ridden for a mile or two after I noticed the gas. Should I use a lighter weight oil?
     
  5. SawyerH

    SawyerH New Member

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    RPM doesn't seem to affect it until I accelerate or its under load. The sound definitely isn't normal. Its louder than the aftermarket mufflers and it sounds like its going to keep spinning/whirring faster and faster. I also don't think the bike is engine braking as it should.
     
  6. Polock

    Polock Well-Known Member

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    could the starter be stuck on. while it's running take the wire off the starter or solenoid
     
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  7. SawyerH

    SawyerH New Member

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    I will check that but I don't believe its the starter running. It sounds more like a starter clutch is not disengaging but I'm not sure.
     
  8. Polock

    Polock Well-Known Member

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    on a 750 you could remove the starter and look in the engine, spin the gear one way and not the other. 550's might be different ?
     
  9. Rooster53

    Rooster53 Well-Known Member Premium Member

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    Check for voltage on the output side of the starter solenoid. If the starter clutch is not free wheeling then the rotating starter will generate a voltage that is dependent on RPM and increasing as you rev the motor.
     
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  10. k-moe

    k-moe Pie, Bacon, Bourbon. Moderator Premium Member

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    +1 If the starter clutch is sticking then the starter motor is spinning.
    Thankfully the starter clutch on the 550 is pretty easy to get to.
     
  11. Polock

    Polock Well-Known Member

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    if the starter clutch sticks somehow, when the motor got to 5K, the starter would be doing a bazillion rpm, it might go into orbit
     
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  12. SawyerH

    SawyerH New Member

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    I'm not sure what happened but I rode the bike all day yesterday and it never happened once. The bike ran great! Thank you all for your help and suggestions!
     
  13. Timbox

    Timbox Well-Known Member

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    Those gremlins are running around in that engine. Glad it stopped doing what ever it was doing.
     

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