Clip on resonance

Discussion in 'General 1000RR Discussion' started by auag, Aug 16, 2016.

  1. auag

    auag Active Member

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    Another problem I have with my RR7 is resonance, mainly noticeable above 4000rpm.
    I can feel it in my feet but critically also in my hands.
    A run on the motorway lasts about 20 mins before partial, then complete numbness in my index fingers and thumbs.
    The symptoms are worse and present sooner in my right hand.
    I've been reading around and it seems to be a long standing problem on bikes. The manufacturers make token gestures with various bar end mass systems but I have to say, a car driver would not be the long term guinea pig.
    I think the only practical solution on a bike, where the engine is hard mounted, is tuned mass damping, albeit possibly needing very large masses, (maybe up to 1kg per bar end).
    Has anyone been down this road successfully, as in got their bars buzz free?
    Thanks.
     
  2. Ian63

    Ian63 Active Member

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    Check if you've got carpal tunnel issue that results in numbness of the thumb and other fingers
     
  3. auag

    auag Active Member

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    I've definitely not got any symptoms of CTS but I run a real risk of that happening by ignoring the nerve impingement I'm feeling on the bike.
     
  4. sps170373

    sps170373 Moderator
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    Aftermarket clipons with carbon fibre tubes would help but not a cheap solution unfortunately
     
  5. auag

    auag Active Member

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    That's interesting, I'll follow that up.
    Do you know why carbon fibre helps? Does it inherently resist transmitting the vibration?
     
  6. Lozzy

    Lozzy God Like

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    I find if I grip the tank, relax my arms & take the weight off my wrists I don't get it. Unfortunately on monotonous journeys it's easy to slid back into leaning into your wrists/hands & without fail I'll get the same symptoms as you. Wearing light mesh summer gloves exasperate's it too.
    I hardly get it wearing the gp pros or thick winter gloves.
    The other half has had it bad with both bmw''s so it's not just the blade
     
  7. sp1n99

    sp1n99 Active Member

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    Agree with Lozzy, it's about relaxing on the bike.
    I cycle every day and get this on my bike, it's just a matter of shaking my hands out to get blood flowing again. I also get a touch of it on the motorbike as well, luckily in the left ( clutch ) hand.
    I, personally, don't find it a big problem. Once you know what it is and how to deal with it then it's just a matter of getting on with it.
    The best thing I did on the blade was fit Stompgrips so I could relax my arms.
     
  8. auag

    auag Active Member

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    I agree with both the above and have experienced the impingement to abate a little when I hold my weight less on my arms.
    This makes good sense as a partial solution because you are changing the damping of the system by varying the use of your body mass.
    Our bodies are very tolerent of vibration generally, it's just that this particular activity puts the load and resonance right through an area where main nerves are close to the surface. A bit like knocking your funny bone sets off a universal response in us all, resting the butts of our wrists on a vibrating beam is a common trigger for digit numbness.
    My goal is to stop the OEM bars resonating, and I think that can achieved using tuned mass damping.
    I think the right amount of mass at the bar end will move the bar resonant frequency to a place rarely generated by the engine.
    The solution for my bike won't necessarily work for other models but will point us in the right direction.
     
  9. sp1n99

    sp1n99 Active Member

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    It's not necessarily the vibration on the bars causing you problems, it's more likely to be impingement of the ulnar nerve due to a combination of things like incorrect alignment of the levers, body weight on the arms, using one or two fingers on the levers etc.
    If it's a blade you're talking about I would be surprised if it's vibration/ resonance causing you problems. A blade is probably the most " sewing machine" like bike I've ever ridden.
     
  10. auag

    auag Active Member

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    Well I certainly wouldn't call my RR7 sewing machine like!
    In-line 4s are notorious for producing harmonics necessitating car manufacturers to spend significantly on subframe mounts.
    Reading around the web every I-4 bike manufacturer has issues, even BMW, which surprised me.
    My symptoms are likely to be median nerve originated since they rarely extend away from the thumb and index finger though it's not an exact science, and if my symptoms go with tuned mass bars then hey ho!
    I agree that weight throught the wrists is a component also, but in this first instance I wanted to eliminate the possibility of resonance being present in the bars from the engine's forced vibrations.
    My intention is to measure the bar vibrations and see if resonance presents at points in the rev range. I'm pretty sure it will be there in spades.
     
  11. sp1n99

    sp1n99 Active Member

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    I found the following from Peter T ( Nov 13), hope it helps.

    Hey I love this subject it is right up my street!!!
    When I had my last blade a 2009 model I had these vibes that came only from the throttle side. At first I thought it must be the bar end weight, so I removed it and lubed the rubber bung which goes into the handlebar and put some grease on the bolt that holds it. It seemed slightly better but did not cure the numb sensation I was getting. After some thought about where this resonance is coming from and why only on the throttle side baffled me for a while. Next stop was checking to see if the resonance was travelling up the throttle cables as this was possible cause for such frequency, but alas no it was not as cables not under tension do not resonate at the same frequency, so it was back to the blackboard!! Then I looked at how the handlebars were attached to the forks and this is where the problem lied!! Hooray, the reason why is because the locating lug was just about touching the the upper yoke and was vibrating at given revs, also I noticed that the clamp was not tight up against the yoke like the clutch side was. After undoing the two allen bolts and pulling the handlebar upwards and inwards the problem was solved!!! No more vibrations and it cured the problem, so much so that when I got my new blade it was the first thing I did and I have no vibrations in my 2012 blade.
     
  12. Lozzy

    Lozzy God Like

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    Damn you Resonance......you vill go ze vay of da Cube...or my name isn't ze Great Auag

    tumblr_n8zbcl90nx1rlw181o4_400.gif
     
  13. auag

    auag Active Member

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    Cheers, I'll add that to the list.
    I assume the lug he refers to is the peg that stops the clip on rotating around the fork leg??
    Once I have an instrument to measure what's in the bars I can say what changes and what doesn't.
     
  14. PeterT

    PeterT Active Member

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    Yes this is a major cause for resonance on all bike. Recently cured my mates KTM 390 which suffered terribly through the bars, turned out the bar ends were loose and the bars were done up incorrectly.
     
  15. auag

    auag Active Member

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    I agree, there are odd issues present that can be corrected on any bike, but the fundamental issue with an engine unisolated from the frame is going to be forced vibration. A loose or incorrectly fitted component does not account for the legion of so called sophisticated sports bikes (mine as an example) suffering from user harming inputs.
    The bike community should not be so tolerant.
    You can pay £14,000 for a new S1000RR and get numb hands. That is unacceptable.
     
  16. sp1n99

    sp1n99 Active Member

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    Perhaps you need to look at an electric bike......
    Having owned two stroke singles and twins, and four stroke singles, twins, triples, straight fours and vee fours I can't ever remember a time when I've found vibration to be a problem apart from having to check nuts and bolts, especially on the big singles.
    Motorbikes aren't like cars whose engines are mounted on rubber mounts, I think vibes are always going to be part and parcel of the motorcycling experience.
     
  17. sps170373

    sps170373 Moderator
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    Look on bikehps website they have some info there about it
     
  18. bonjo

    bonjo Active Member

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    I suggestst you try products like grip puppy. I hasve a yamaha single adventure bike well known for terrible handle bar vibes (like most singles I guess). I put a pair of these on for £15 they do a great job. They also make the grip size a little bigger so be careful if you have small hands
     
  19. Slimwilly

    Slimwilly Member

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    Fat grips may help, I have oxford heated grips, steel bar weights, just done 2400 miles ten days , no vibes on my 09 blade.I do though get hand finger ache, but relaxing, moving weight ,bum position now and then sorts it. Hope you get an answer from your bar reading vibey machine.
     
  20. auag

    auag Active Member

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    Ok, thanks for the helpful pointers.
    Tried Grip Puppies, they knock a little off for sure but not an answer, IMO.
    Carbon bar tubes are interesting, insofar as they do indeed have an affect on vibration transmission but I'm somewhat warey of them and still feel the answer is closer to home.
    Started tests of different weights and have a 'rudimentary instrument' to confirm what I can feel.
    So far my subjective results are that a considerable increase in bar end weight is needed to kill the problem in the 3-6000rev/min range used on the motorway.
    Incidentally, I asked an ex-colleague who's still in engineering to close his eyes and hold the bar end as I revved my RR7 from tickover to about 8000rpm. He laughed his head off, if that was a hand-held breaker or compactor you'd never be allowed to sell it.
    Bikes are in the Stone Age.
     

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