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  • Vibration

    Gen 1 Approaching 160k miles. Since about 120k its been buzzing more and more. Puts my hands to sleep even on moderately short rides. Carbs balanced, compression even and very good across all 4, valves in spec and have never needed any adjustment since day one. Looking for ideas. Front motor mounts maybe? Is this a common issue?
    -=Hannibal Ad Portus=-

  • #2
    Vibration is common, severity is what differs. Cupped tires? Kinked chain? Worn sprockets? TPS out of adjustment?

    Worn tires/ chain/sprockets can add a lot of vibration.

    Try loosening your four handle bar hold down screws and re tightening them.

    Try running for a while with the TPS loosened enough so you can move it with your gloved fingers while you ride, see if you can find a TPS position that has fewer vibes without throwing RPM code.

    You could loosen and re torque your motor mounts but I doubt that's it but it was a popular thing to try back in the day.

    Do you hear a a vibration sound or just tingle in the bars?

    I resort to grip puppies myself.


    • #3
      Have gone through many tires and chains/sprockets. Well over a million miles on 2 wheels through my life, better part of two million if i were to guess. I’ll check the tps but its tight and in spec as far as the manual goes. I’ll try the tps trick. At this point i’ll try most things.

      nothing audible but you can see and feel it in the bars. Tried several different bars to try to mitigate to no avail. Mirrors and levers dance nicely through the offending rpm ranges.
      -=Hannibal Ad Portus=-


      • #4
        What is the offending RPM that causes the vibes. Can you see the mirrors dance when you're parked on the center stand and in neutral or does it have to be in gear to vibrate? It would be nice if you see it on the stand for doing TPS adjustment while stationary.

        My bike has higher miles on the frame but similar miles as yours on my second motor. I never hear the plastic rattle or see the mirrors dance at any speed, but I do sense vibes while in motion as the rpms increase. Worst at 5K rpm, so mine may be more drive train related than motor. I know you want a mechanical solution but have you tried GripPuppies?

        PS on those TPS tighening screws if you haven't already it's good to change those to stainless socket head bolts. With the socket heads you can stick a allen socket in it to hand tighten or loosen while on the move. The oem tamper resistant bolts suck.


        • #5
          About 6k is the worst of it. I thought about different grips but thats addressing the symptom and not the disease. When i reach down and touch the engine throughout the rpm range it does not seem to vibrate noticably more or less.

          another possibility may be some sort of cavitation in the carbs. Possibly worn diaphragms/ slides. I’ve seen excessively worn carb’s slides flutter. Kinda spitballing now.
          -=Hannibal Ad Portus=-


          • #6
            If you go back to FZ1 early days circa 2002 with Jinx (no real expert), he was an advocate of the rubber cross over tubes that linked 1/4 and 2/3 carbs. It was suppose to promote smoother carb operation and less vibes. I made one and installed it for a few months but never noticed much difference, so I took it off and never looked back.

            We all had low mile bikes back then and many still vibrated. So it was a common problem. In line four bikes are going to vibrate the most where the torque and hp curves cross around 5400 rpms, it's what they do. I know your response will be "yea but it wasn't this bad before". I hear you.

            Did you try making changes to the TPS with bike on center stand? There isn't a ton of range/movement on the tps adjuster and it shouldn't take long to see if it will help. I know I posted up 15 years ago that that's what I use the TPS for instead of more performance. For me, 2% more performance wasn't as important as reduced vibes.

            One reason I threw a replacement motor in at 150K was my compression was low enough that the carbs didn't operate properly. I don't think the engine was producing enough draw on them (In line four COPD).

            My embrace of grip puppies is due more to my clutch hand developing carpal and carrying my weight than it is for vibes, but they work for both.


            • #7
              My worst vibration issue was not realizing I was gripping the bars too tight - once I trained myself for a loose grip, I really never noticed the vibes again....
              Last edited by rswebscan; 08-11-2021, 05:40 AM.
              Why are we here? Because we're here....Roll the bones


              • WileECoyote
                WileECoyote commented
                Editing a comment
                Amazing what relaxing and allowing the bike to work for you can do. I have (had) a severe problem with this. I learned watching Bmidd and Iluvmyfz ride as well as others. Embarrassed to say, I am NOT smooth what so evahhhh.........

            • #8
              Here's a link to Pat's page vibration issue


              FUZ1ON's thoughts

              There is a fine line between "hobby" and "mental illness."
              Naked FZ1's can be a lot of fun. Bike Pics
              Current bikes: '82 CBX, '04 FZ1 (skunk)


              • #9
                There's always heavier bar end weights. Ideally you could rubber isolate the bars where they are clamped to the risers, but it causes too much rotational movement. Engine vibration is common to most motorcycles, sometimes manifest at the bars some times at the pegs. I don't think they make Grip Sockies, you have to wear Frankenstein boots.


                • #10
                  More spitballs: how about a tire that's de-laminated? Maybe check your tires for a soft spot......


                  • #11
                    Its been an issue for 10+ sets of tires at least.
                    -=Hannibal Ad Portus=-


                    • #12
                      At speed, pull in your clutch lever. IF the vibration is still present, then you know that your problem is originating from your drivetrain or wheels/chassis. IF the vibration subsided when you pulled in the clutch, then you know that it's coming from your engine. Here's some ideas:

                      Ignition & power balance: Pull each of your plug wires back so they're just sitting on each spark plug, Rev your bike to 2500 or 3k rpm, and while holding the rpm steady, remove each plug wire - in turn & read the rpm drop once you've backed the wire far enough away from the plug to disconnect it. Each cylinder should drop by exactly the same rpm. If the rpm drops less for any given cylinder than the next, then either your compression or ignition is weak for that cylinder. If you post back with that result, I can help you narrow it down further from there.

                      Assuming you did the above test & determined that each cylinder drops by the same rpm amount, then try this:
                      I"ve found that my bike is very responsive to vibration reduction from doing really accurate valve adjustments. I know you said yours are properly adjusted, but are you really certain they're within .001 of each other? I know it's a pain, but use the go/no-go technique and take your time to be as accurate as you possibly can. I used to have vibration in my bars & this is what made the most difference. Fwiw, I tried a number of the usual mitigation techniques including bar weights & grip puppies, & valve adjustment is what helped the most. It will likely never go away completely without major engine work(I balanced my pistons to within a tenth of a gram), which is one reason why I run a taller(larger) front drive sprocket.

                      Finally, check your carb diaphrams for pinhole leaks by holding them up to the light and gently stretching them out a little to see if any light shows through. Do this at least 4 times for each diaphram, as you rotate each of them into different quadrants(around the clock face) stretching them to examine for pinholes or cracks. You also need to check that your mixture is even in all cylinders by adjusting the needles. For my bike, I run different needle positions for the middle 2 cylinders than the outer 2. This produces the best performance & smoothest engine response. Bottom line is, you need to give each cylinder whatever it needs. You DON"T just set them all to one position and call it good, if you care about tuning it properly. YMMV(literally) ;)


                      • #13
                        I was doing something today with the handle bars on my Gen 1. I noticed that it didn't take too much effort to move the risers forward and back a tiny amount. I only bring it up because under the top triple tree is the bolt from the risers. The bolt has a thick rubber washer held down by a steel washer, and the securing nut. Tightening didn't change the vibration, but I forgot that the washer was there and it theoretical should have a minor effect on dampening vibes in the bars.


                        • Fozzy1
                          Fozzy1 commented
                          Editing a comment
                          My 05 with 55,000+ miles has the same riser damper issue. Still haven't bothered replacing them since I don't notice any sort of extra vibration, nor any all around sketchiness. Only thing is occasionally squaring the bars/risers which only are a tiny bit off each time.
                          I'm surprised the two lowsides she's had over the last year hasn't done anything more to them.