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ZL600B Excessive vibration

Zed Phillips Sep 2, 2019

  1. Zed Phillips

    Zed Phillips New Member

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    Hi peeps, I’ve owned a number of Kwaks over the years including the VN750 twin but never had a Kwak that vibrates as badly as the ZL6B I own. It is worst just under 3000rpm but is present across the entire rev range. Is this “normal” for a ZL6 or is there some common failure point like the engine mounting becoming hard with age?
     
  2. 87kawzl

    87kawzl Supporting Member

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    Probably need a tune up and carb sync. I4's should run smooth but sometimes a bit of a buzz gets through to the throttle hand after an hour or 2.
     
    wuputt likes this.
  3. Ed

    Ed Well-Known Member

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    My 600A has a good buzz in the headlight bucket at those RPMs but nothing excessive felt thru the bike. My Bolt started doing the same thing along with the tag cracking.
     
  4. R. J.

    R. J. Supporting Member

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    :hello: All bikes create some sort of harmonic resistance frequency. That is why fuel tanks and motors are rubber mounted to the frame. When my gromets went bad on my fuel tank my gas gap buzzed and it also transfered to my head light. Also my mirrors at idle (1150 RPM) was fuzzy more than usual and I felt it through the left handelbar grip. ZED: Does the whole bike vibrate?
     
  5. Zed Phillips

    Zed Phillips New Member

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    Yes the whole thing vibrates. Previous owner put soft grips on so I guess he never solved the issue. I've added a custom made deep foam seat to stop my arse going numb but the vibration though the bars makes 70 plus miles on the bike more like a torture session. Still great for short blasts in town though, but this vibration is unusual for a Kawasaki, they normally take grate care to eliminate it. By comparison my VN750 twin which you would expect some vibration from was really sweet. I'll need to put my gauges on it and see if the carbs are in sync, but tick over and mid range seem sweet on take up.
     
  6. Ed

    Ed Well-Known Member

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    The VN750 and a lot of other bigger bikes including ZLs have a counterbance but not the 600.
     
  7. markus56

    markus56 ZL-OA Co-owner Staff Member Administrator Super Moderator Supporting Member

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    The big ZL's don't have a counter-balancer and never have had one.
     
  8. Ed

    Ed Well-Known Member

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    I saw it on one of the old inline fours. Or am I mistaken?
     
  9. R. J.

    R. J. Supporting Member

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    :hello: Does the ZG 1000 connies have a counter blancer. ZED: How many miles is on your 600.
     
    prfixer likes this.
  10. markus56

    markus56 ZL-OA Co-owner Staff Member Administrator Super Moderator Supporting Member

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    Yes, Concours have had them from day one but not the big ZL's.
     
    wuputt likes this.
  11. R. J.

    R. J. Supporting Member

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    :hello: Thanks MARKUS. ZED. Check your wheel bearing. Also My 1983 HONDA CB 650 SC Nighthawk had a viberation problem and it ended up being the bearings in the bevel gear assembley but it had 90 K miles on it when the bearing went bad. Then at around 100 K miles the # 3 crank bearing went out. :pain10:. I found a donner bike that was wrecked for $300 with 13 K miles on it so I did a motor swap.
     
  12. Harriminator

    Harriminator Senior Member

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    If you build in a Connie engine into a ZL-frame you have one...:laughing7:
     
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  13. Ed

    Ed Well-Known Member

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    I think all the big Kaw 4's from 900 up now use counterbalancing.
     
  14. Harriminator

    Harriminator Senior Member

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    The idea to omit the 'cb' was to have less mass for a better acceleration; a comparative test on the track showed that the GPZ900R was even quicker than the ZL900 after several trials...looks like the whole thing backfired, Japanese Super Engineers.:roflmao::thumbsdown:
     
  15. 87kawzl

    87kawzl Supporting Member

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    ^ not a fair comparison! The GPZ was tuned for top end and the ZL was tuned to be a boulevard cruiser where things either get handled 1/8 mile at a time (light to light) or it's a roll on situation. I'll bet the GPZ had to drive around the ZL to get it's better time in the 1/4.
     
    wuputt likes this.
  16. Ed

    Ed Well-Known Member

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    A counterbalancered crank can be lighter for the same amount of vibration but has more frictional loses.
     
  17. Harriminator

    Harriminator Senior Member

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    I was outpaced two times on my Eli (and I gave everything):
    1. Honda NS400 R street legal :eek:
    2. Mercedes-Benz AMG :eek::eek:
     
  18. 87kawzl

    87kawzl Supporting Member

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    That's why they make the H2 nowadays...lol
     
  19. R. J.

    R. J. Supporting Member

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    :hello: I was smoked by a 1985 Mustang Convertiable with a roll bar. :laughing7:. Come to find out it had a highly modified 428 Cobra Jet motor. The guy told me that it will run low nines in the 1/4 mile.
     
  20. Ed

    Ed Well-Known Member

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    The engine mounts seem to be the main determining factor. Sport bikes are solid mount to reduce the frame and use the engine for load bearing instead. My 60º V-twin 950 has a double cradle frame, solid engine mounts and no counterbalancer. Red line is only about 6000 rpm so it feels like a nice rumble instead of an annoying buzz.
     

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