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Hit the power limit of the Kat or just of my old bike ?

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  • Hit the power limit of the Kat or just of my old bike ?

    Here is how :

    going uphill on the way to Mount Washington on Route 16 ( I believe). I have a passenger ( about 130 pounds) myself ( 160 pounds) and my old bike ( '89).

    And in 6th gear at about 70 mph I tried to pass a truck while going slightly uphill. And I opened the throttle all the way (there was about half left to be opened I would say) and the kat .... well.... did nothing.

    And also on the way back we hit about 90 mph for a short portion. I didn't wanted to go faster, but it seemed possible if it's flat enough.

    The question is : am I loosing power or is it normal for the Kat ?

    W.

  • wittymonkey
    replied
    Ok , I am aware about the harmonics (I am electrical engineer) so I note that I need a carb sync and or valve adjustment and or to make the bars havier

    And in the mean time be carefull to let the blood flow all the time ...

    Thanks a lot, it's really good to know,

    George

    Leave a comment:


  • The CyberPoet
    replied
    Originally posted by wittymonkey
    Ok, tonight I road it and pushed it over 7k up to 10k and indeed the vibrations are less important.

    What does this mean ?
    This means that you happen to have a harmonic or sympathetic harmonic vibration somewhere around 5500 - 6k, which is common on the Katana for some bikes (doesn't happen to every Katana).

    Q: What is harmonic vibration (sometimes called sympathetic harmonic vibration)?
    A:
    Every item on a motorcycle (or in a car, etc) has some frequency that it naturally wants to resonate at. Just like a bell or a tuning fork has a specific frequency when you ring it, parts of the bike have the same tendency, especially the handle bars (which are a hollow tube, and thus like a type of bell).
    If you take two tuning forks which are tuned to the same frequency, start one vibrating, the other will start vibrating too if it's within audio range. Why? Because the sound (which are vibration waves through air) are at exactly the right frequency to push against it at exactly the right instances to build up the second tuning fork's shaking. This is called harmonic vibration. It doesn't even have to travel through air -- it can just as easily travel through any solid material (such as an I-beam, or in our case, the frame or triple-trees of the motorcycle).
    Thus, when something in your engine, transmission or wheels happens to hit the right frequency to hit the frequency of the handle bar extensions, they vibrate... and if it happens to be at a frequency that messes with your nerve sensors, you get tingley hands (which can lead to more complicated problems, including Raynaud's disease aka Raynaud's syndrome).
    So how do you stop it? You have two basic methods:
    By changing the mass of the bell or the tuning fork, you change the harmonic frequency -- in the same sense, the Katana normally uses a very heavy (compared to most bikes') set of bar-end weights designed specifically to help keep the harmonic frequency out of the range of what the bike normally sees. Increase the bar-end weight, or the bar-weight itself (by filling it with lead or BB's & silicone or epoxy, etc), changes it's vibrational frequency.
    The second method is to track down the origin of the vibration and stop it from happening there (such as sync'ing the carbs and doing a valve adjustment, to the more extreme "balancing the engine's rotating masses").
    Obviously the first method is easier. Thus, if you removed the stock bar-end weights (or replaced them with light-weight replacements), put the stock ones back on. Or get even heavier ones. And then start thinking about weighing down the bar extensions themselves more heavily (commercial products like the "Bar Snake" fill this niche, as well as the home-remedies I listed above).

    On a separate note: if either of the bar extensions are unevenly bent compared to the other, this sets up a different kind of vibration that can't be cured by increasing the mass of the bars -- the only good solution is to replace the bent bar with one that isn't bent. This is a frequent occurance in bikes that have been dropped and the bend is small (a few degrees, barely even noticable) -- taking the bars off and laying them against each other will let you see immediately if one is bent at a different angle than the other.

    Finally, a word on nerve damage, Raynaud's syndrome (or Raynaud's disease, sometimes called Renauld's disease) and long term risks of riding with bad vibrations. If your hands regularly get tingley from riding, you need to address this issue by either undertaking one of the above fixes or by otherwise damping out the vibration (such as use of gel-palmed gloves, throttle rockers, and/or cruise controls). Failure to do so can result in multiple medical issues with your hands/fingers/wrists, including permanent damages and even cellular death (which can lead to gangrene and amputation in the most extreme of cases). The vibrations can cause disruption of the blood supply in the smallest capillaries, depriving the cells of oxygen, and can also cause your nerves to basically short-wire themselves from too much systematic false input (leading to symptoms of pain or numbness that may be permanent, as well similar reactions at the hands when emotionally triggered in the future). White splotchiness on the palms is often an early symptom... Unfortunately, (according the FDA and the center of rare diseases) much of the info out there on Raynaud's is poor, inaccurate or dated -- the most common sufferers are those who used power tools or other vibratory devices held in their hands for years prior to diagnosis; the subsequent symptoms (post-onset) are usually quoted as being causal when in fact they rarely are. Cold exacerbates the problem because blood flow into the capillaries is already restricted by the body's natural attempts to restrict heat loss, and thus in cold weather this is even more likely to occur.
    The picture below are the hands of a 43-year old male sufferer -- and no, he did not just let go of a set of handlebars or other item; the discoloration is now permanent from the damages associated with Raynaud's:

    Look up Renauld's disease for more info.

    Good Luck!
    =-= The CyberPoet

    Leave a comment:


  • Mojoe
    replied
    Originally posted by wittymonkey
    Hmmmm, I will try this. I never spent enough time after 7500 rpms to check the vibrations. I just don't like not beeing nice with my engine... but I will try for this purpose.

    Thanks,

    W.
    actually, by always keeping the low rpms like you are, you are NOT being nice to your engine. They vrave being opened up. It keeps them clean. 2 summers of driving like you do, and open up the engine....I am betting you will see a significant carbon build up on your pistons and valves.

    Leave a comment:


  • wittymonkey
    replied
    Ok, tonight I road it and pushed it over 7k up to 10k and indeed the vibrations are less important.

    What does this mean ?

    Leave a comment:


  • wittymonkey
    replied
    Sounds like a lot of fun, 2nd gear , 9000 RPMS ! I WILL try !

    Leave a comment:


  • The CyberPoet
    replied
    Originally posted by wittymonkey
    Hmmmm, I will try this. I never spent enough time after 7500 rpms to check the vibrations. I just don't like not beeing nice with my engine... but I will try for this purpose.
    Your engine is designed to run up to 10.5K RPM or 11K RPM or some such (it's marked on the tach as the redline), and anything about 1000 RPM below that and down even for long periods of time isn't "abusing" your engine as long you are using good motor oils and giving it the maintenance it needs on schedule.

    Cheers
    =-= The CyberPoet

    Leave a comment:


  • wittymonkey
    replied
    Hmmmm, I will try this. I never spent enough time after 7500 rpms to check the vibrations. I just don't like not beeing nice with my engine... but I will try for this purpose.

    Thanks,

    W.

    Leave a comment:


  • The CyberPoet
    replied
    Originally posted by wittymonkey
    It's just vibrating soooooooo much I hate doing more than 6k rpms.
    Oh, one other thought: the vibrations that start at 6k may go away for you by the time you get to 7500 RPM and remain gone the rest of the RPM range... try it and see

    Cheers
    =-= The CyberPoet

    Leave a comment:


  • SlipKid
    replied
    My suggestion would be to start saving for a Kat 1100 or an FJ1100/1200 or something like that if you are going to do much 2-up touring type stuff. That'll be all the power you would need. With what you could sell the Kat for, it wouldn't be much extra money to procure one of those bikes.

    Leave a comment:


  • Matt
    replied
    Originally posted by wittymonkey
    It's just vibrating soooooooo much I hate doing more than 6k rpms.

    6K is where the power STARTS on the 600, no wonder you couldn't pass.

    If you haven't had the [initial] valve adjustment done, make sure to get that done, it makes a world of difference.

    Leave a comment:


  • md86
    replied
    Originally posted by The CyberPoet
    Originally posted by md86
    Huh , I have good enough passing power from about 4-5 grand on up . I've passed MANY cars going 50-ish from 6th gear with no problem .
    290+ lbs on a '89 600 with an uphill road-grade is way different than you on a '93 771 (with it's 13:1 compression ratios) carrying just you...

    Cheers
    =-= The CyberPoet
    Well , I was thinking under "normal" circumstances , you know ? Just rider , no hill . But yeah , I forget how little power the stock 600 feels compared to mine . Never rode one all that much , but I did notice right away that I could NAIL the throttle coming out of a corner and not worry one BIT about anything bad happening , it seemed .

    Leave a comment:


  • Anonymous
    replied
    Irregardless, you have to go above 6K on a Katana...I mean, that just where the fun begins

    Leave a comment:


  • The CyberPoet
    replied
    Originally posted by md86
    Huh , I have good enough passing power from about 4-5 grand on up . I've passed MANY cars going 50-ish from 6th gear with no problem .
    290+ lbs on a '89 600 with an uphill road-grade is way different than you on a '93 771 (with it's 13:1 compression ratios) carrying just you...

    Cheers
    =-= The CyberPoet

    Leave a comment:


  • md86
    replied
    Huh , I have good enough passing power from about 4-5 grand on up . I've passed MANY cars going 50-ish from 6th gear with no problem .

    Leave a comment:

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