VFR800 99 vibrations related to engine speed

Discussion in 'General VFR Discussions' started by Marke, May 21, 2017.

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  1. Marke

    Marke New Member

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    Hi Guys,
    I've been a long time reader but a first time poster. Took some time to get the password etc sorted out.
    I have a VFR800 99 with 125,000 kms on the clock and it still runs runs etc.
    I've had the bike since 100,000 and done my own maintenance and repairs.
    I have an issue which I can''t resolve and looking for some help.

    Issue:
    The bike has a vibration through the throttle which puts my hand to sleep. I understand VFR's are supposed to be silky smooth.
    For a short ride it OK, but over a longer distance it certainly is a pain.
    It comes on more noticeably at 6,500RPM. If I place my hands on the bars I can feel it and also through the pegs.
    I say it's in the engine because if I pull the clutch in when moving the vibes follows the engine, not the bike speed.
    If I pull the clutch in at 100 km/hr and let the engine idle to bike is silky smooth.

    History:
    To date here is a summary of things I have tried. Some helped, some did not.
    In no particular order:
    • checked and reset shims on valves - no change.
    • replaced head stem bearing - it did need it, but no help
    • replaced front wheel bearing
    • rebuilt fork forks
    • fitted foam 'pussy grips - not sure if they helped
    • put another clutch basket in from the wreckers. Mine was warn where the plates touch the slots. Noticeable improvement. Also made changing into 1st much better. Suggest clutch was dragging.
    • balance throttle bodies - this helped I think by taking the noticeable vibes point up to about 6,500 instead of 5,500
    • balance wheels, new tyre (as mentioned the vibes are related to engine speed not bike speed, but just to rule out)
    • Adjust chain, check for wear (as mentioned the vibes are related to engine speed not bike speed, but just to rule out)
    • service, air filter, oil etc
    • tried different maps on PC
    • fitted heavy bar weight ends

    I'm just about out of patience and not sure where to look next.

    I'm fairly certain it's a mechanical out of balance but wonder if the injectors are out of balance, ie one partially blocked or bad lead/coil/plug.
    I did try and shut the motor down with the kill switch while riding down hill at 100km/hr to see if it was 1 cylinder not firing as well but it was hard to tell anything.

    Any suggesting would be greatly appreciated.

    Regards Mark.
     
    Last edited: May 22, 2017
  2. Terry Smith

    Terry Smith Member

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    My 99 is not what I would call silky smooth but it is not hard on my hands at all. The V4 engine doesn't have a high pitched in-line 4 vibe, more of a lower frequency shudder, and mine is also at its worst around the same revs as yours.

    Have you considered that you might be the problem? I went through increasingly tingly/numb/cold hands which I thought was just a response to cold/poor circulation or too much weight on my hands, but in fact I was developing carpal tunnel syndrome. I had surgery and my problems disappeared. Maybe you could consult a physician?
     
  3. Marke

    Marke New Member

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    Hi Terry,
    Yes, my mate says the same.:smug:
    However, there are definite vibrations I can feel.
    I had tried making sure I have a relaxed grip, not locking my arms straight, siting up straight, leaning forwards etc.
    Good point you raise but I don't think so.
    Regards Mark.
     
  4. GreginDenver

    GreginDenver New Member

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    Do the handle bars have the original bar end-weights installed? Or did somebody replace the originals at some point in the bike's life? Bar end-weights are very specifically selected to prevent the sort of bad harmonic resonance you're describing.
     
  5. Marke

    Marke New Member

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    Hi mate,
    I forgot to mention I purchased heavy bar ends and they helped a little I think as well.
    I haven't removed the bar ends from inside the tube but they do feel 'rubbery' still.
    Good point but been down this path.
    Thanks and regards Mark.
     
  6. vegaquark

    vegaquark New Member

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    I have the same problem, but my bike becomes smoother as it warms up, i mean, after a 30 min ride, it starts to feel better, if like the oil took long time to warm up and reach all places.
    Could it be a worn out oil pump? I'm running 10w50 motul 7100 oil.
     
  7. Marke

    Marke New Member

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    I was pondering the oil pump, only because it's driven with a little chain and therefore a moving part. I'm not sure if the chain wears like the dive chain. It's small however when compared tot he clutch basket.
    I think if the oil pump was bad I'd have other more pressing issues.
    The light doesn't come on.
    I'm using Motul 5100 oil, changed every 5k.
     
  8. OZ VFR

    OZ VFR Member

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    I hear this many times, but have yet to see a siky smooth VFR.
    They all vibrate a bit, some more then others.
    Accurate throttle body balancing is very important, and hard to do with cheap analog gauges designed for carbies.
    They are also supposed to be set to different settings, not all equal.
    Went through this with my bike, and playing with TB's made a difference, but it still vibrates a bit.
    The original rubber mounted front sprockets make things a bit better on some bikes, but not sure if you can still get them.
     
  9. Marke

    Marke New Member

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    Hi Oz VFR,
    Thanks for your post.
    I did notice an improvement when balancing the throttle bodies but was using a cheap single gauge that was probably not that accurate for the small vacuum increments.
    I'm aware they are not all the same reading. If the feedback indicates it seems to be related to balancing I'll find another gauge and do it again.
    Not sure of my front sprocket type but when the clutch is in it very smooth so I don't believe it's related to the drive train.
    Regards Mark.
     
  10. JIMLARCH

    JIMLARCH New Member

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    Have owned a 3rd and 4th gen. I wouldn't say either one is silky smooth. They have the v4 rumble vibration which I got used to and don't really notice. Test drove a cbr500 the other day which was gutless but silky smooth. Got on my vfr afterward and noticed how rumbly the vibrations were. Seemed really to vibrate a lot in comparison. But I prefer the v4 rumbly vibration compared to the inline 4 buzz.
     
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