What's the buzz, tell me what's a happening

FJRs vibrate. They all do to some extent. You may be too numb to feel it, but it's there. It happens because it's an inline 4 cylinder engine with even firing order, so the two inboard pistons, and two outboard pistons run in tandem. All of the reciprocating masses are in one of two states, similar to how an inline two cylinder engine would.

The designers attempted to nullify the primary engine imbalance with counter rotating balancers, but they are not totally effective at eliminating vibration at its worst, which is typically at around 4k rpm and above.

To make matters worse, in the 3rd Gen engine redesign, Yamaha eliminated the ability to tweak the throttle plates to try and null out any of the secondary vibration due to small differences in fueling at higher rpm, so the 3rd Gens may actually have more vibration at those engine speeds than some of the earlier models.

Designers isolated the 3rd Gen rider from these engine vibration pretty well with the new type of thicker foot-peg rubber covers. And the seat is well isolated from the frame by the fancy rippled rubber bumpers it sits on (ever notice them?). The remaining primary contact point where the vibration can become bothersome is at the handlebars, and this is where I primarily sense "the buzz".

Is it horrible and offensive? No, and no. Does it make riding the FJR long distances (or short ones for that matter) somewhat less enjoyable? Yes, to a certain extent that varies by individual. The pertinent question is: Can the handlebars be somehow isolated from the vibration? And if so, why wouldn't you want to do that?

What started me thinking about this topic is that I recently removed the Suzuki Vstrom hand-guards that I had fitted to my 2014 for the added cooling during the upcoming summer months. At the same time I removed the 1 lb. jumbo bar ends that I had transferred (along with the hand guards) from my 1st Gen to the 3rd Gen. The eye opener was that when I took a highway ride the following day, the vibration level reaching my hands was reduced enough that I noticed it. Not gone entirely, but reduced by maybe half. So somehow, those heavy bar ends were mechanically amplifying the vibration in the bars at that specific frequency.

Well, thinks I, if one weight on the bar end can amplify the vibration, there is probably another one that would nullify it. The trick would be measuring the amplitude and frequency of the vibes and doing a series of experiments to see what combination of weight or weights it takes to null it out.

The other opportunity after establishing the offending frequency of vibration , would be to design some sort of visco-elastic isolation layer / boundary between the buzz source engine and the handlebars. If the vibes never get into the bars we don't have to null them out. That may actually be the easier solution. Of course it could not affect the feel of the steering or it would not be acceptable. But my experiences at work say that vibration isolation can often happen with some fairly firm cushion layers that are of the precisely correct material for the frequency you want to block.

Unfortunately, I do not have an expensive accelerometer at my disposal to measure the vibration amplitude and frequency(s). I tried downloading an iPhone app that has a nifty accelerometer feature (iPhones have some crazy sensors in them, including one for g-force) but the sampling rate of the sensor is too slow to be of much use for this experiment.

I suppose that we could use tactile feedback, but subjectivity is the enemy of a good design process. It would be much better if it could be measured and bench-marked before designing or trying possible solutions.

Thoughts?

Rookie with the multiple postings of one topic. Didn't you read what you were supposed to when you signed up for the Forum? :lol:

Wordy bastard aren't you?

Again, the observation would be subjective, but you might be able to mount a small mirror with a long stalk to the bar using something like a screw clamp. A buzzy bar results in a blurred view. You might tape a small glass bottle half-filled with water to the bar and observe ripples due to vibes as well.

It would be nice to find something quantitative that could be used while the bike is actually moving. Qualitative observations are only useful when they are dramatic but the above suggestions might be an improvement compared to just the feeling.

Had a quick look on-line and apparently you can get an inexpensive vibration meter for something under $200. Have a look at the first couple of selections here:

https://blog.mide.com/6-ways-to-measure-vibrations

I think what is needed are bar end weights that vibrate at a frequency that counteracts and masks the vibration of the bars. Now to figureout the frequency that is needed and to develop a device capable of vibrating at that frequency will require some pretty sophisticated equipment... or will it. I think I've found a way a rider can use trial and error to find the right level of vibration that will make the ride pleasurable. One only need to get two of the widely available devices pictured below, insert a device in the each of the bar ends (some modification may be required) and adjust the vibration level to the level required.

Yeah, I had a 1979 Yammy XS Eleven and 1980 Yammy 850 triple. They had some sort of "isolated" handlebars. Loved them at the time cuz I just road farm roads from here to way over by there in Okieland.

They would SUCK on a sportbike or sportstourer...because of too much deflection of the handlebars...really weird feeling.

I have a Gen3 FJR. Life sucks for those that aren't me.

Edit: Vibes must vary from machine to machine, because mine has a nice healthy engine and the appropriate amount of vibe feedback. My gloves just must be super awesome.

Edit2: Heck, I know atleast 4 old codgers that went coast to coast and I did not see one remark regarding vibes. What da heck! You musta gotta bad 'un!

Edit3: Like the title.

I just love the JC Superstar (double entandre) in the title.

Check out www.manicsalamander.com as has many experiments w/ vibration.

I also thought about using a Throttlemeister as a bar weight (and redundant cruise) (over 80 mph) to quell the buzz.

Fred,

My guess is that removing the bar end weights off the end of the bars raised the natural frequency of the handlebar 'system'. If Yamaha did their homework, the handle bars would have a natural frequency well above any frequency that normal operation of the motorcycle could excite and cause amplified vibration levels. Adding the weights in the first place may have dropped the natural frequency to a range within which motor vibration could have hit a resonance in the bar system (bars and weights)

I believe you could find a weight that could be used to 'tune' the natural frequency of the bar to avoid harmonics through the normal rpm range of the engine. Of course engine vibration isn't the only source of input energy that causes vibration. Road surface and aerodynamics can also induce vibration felt by the rider. Not to mention tire imbalance etc, but those are much lower frequency, albeit usually higher amplitude.

If you had the right equipment you could vibrate the handle bar 'system' on a shaker and measure its dynamic properties and experiment with various weights to tune the system. But that's no simple task. Simulating other sources such as road and aero inputs on a stationary shaker table would be challenging.

I'm guessing that Yamaha has done a good job with the OEM set-up and that big changes such as bar ends and all the other farkles we love to bolt onto our bike probably affects handlebar comfort in a negative way. I say that because I've never felt that FJR vibration to be a big problem. Maybe because I've been riding I-4 Japanese bikes for so long and the FJR is the smoothest I've ridden.

That said, I know 4000-4500 RPM is a range a lot of folks say they experience vibration. It may be that Yamaha has done all they can within reason to tune it out and we're living with the best compromise of cost/weight, etc.

I still maintain that the buzzy handle bars are no big deal when you aren't holding on to them. Over half my long distance riding has me resting both hands on the fuel tank. Even in high cross winds out on the open Montana highways (rte. 2 east of Rocky Mt. N. Park) is quite doable. Use that YamaCruise control you paid so dearly for, and LET GO.

Brodie

Since I ride in the 6-8k range in the twisty roads down here...I must not be in the resonant range. All I know is that I love the sound and vibe of that Gen3 motor!

Honda's ST1300 has a rubber isolation cushion within the handlebar mount. It was very noticeable when we strapped it down with the Canyon Dancer and that was one of the reasons I will never use that product again. I never noticed any flex in the bar mounts when pushing that bike hard but then I may be insensitive.

I notice a lot of vibration at interstate speeds if I shift my feet back to rest on the passenger pegs. Other than that I just accept that vibration is a result of having That Motor in my Motorcycle.

First off: I pressed the post button and waited for over a minute. Then I opened up a second browser window and navigated to the Technical subforum to see if the post had "made it through" without updating on my screen (sen that before). Then I waited a while longer before clicking on "Post" button a second time, which seemed to work in the normal (slow) amount of time. Blame me if you wish, but I would say the software or its implementation is at fault for the double post.

As I thought I made clear, this little "feature" is not a serious issue; it's a little niggling one. And I wouldn't have even raised it at all if it weren't for my recent observations after removing the oversize bar weights, which will obviously not be going back on.

Yes, I can man-up and tough it out, or I could let go of the bars. But... if there is a way to totally eliminate the vibration from the handlebars, and it didn't require making them float around like Wheaton's dreaded examples, or have any other negative results on the bike, who here would not want to eliminate the buzz?

From my observations, the vibration amplitude at 5-7k rpm is not much less than at 4-5k rpm amplitude, where it seems to start. You just tend spend more time at 4-5k rpm riding the bike around town, on the freeways, etc. I'll have to be more observant now that I have eliminated the overweights.

Thanks to the link to manicsalamander (not the brand weights I have, FWIW). I'll check that out and see if it leads anywhere.

And special thanks to FJReady for his serious and well educated insight.

I think what makes my oversize bar ends NOT work as intended is that they screw into the stock floating rubber mounts inside the bars, that were intended by the design to have a much smaller weight hanging from them. You can't just hang a bigger weight on the end and expect it to be better.

Now... if the weight were more directly coupled to the handle bar it might actually have a positive effect, so maybe it needs a stiffer rubber mount to maximize its damping ability at XYZ frequency. In any case I (now) know that it is more involved than just adding more mass to the weight.

edit - Almost forgot to thank Ross for his post. Some of those measurement devices look reasonable. I may be able to get my employer to buy something like the Fluke meter, say it's for work (we do have a need for something like that) and use it on this project. At work we are generally looking for vibration caused by rotating machinery, so the vibration frequencies are typically pretty low (20-30 Hz ranges) but we like to look up to about 100 Hz. Some of those devices don't have sample rates fast enough for what we are looking to do..

Seems that Manic Salamnder's approach is to directly mount (metal to metal) their inertial mass. Might be worth considering.

Maybe try filling the handlebars with Dyna beads?

Compared to most of my bikes current and past, the FJR is smooth as silk. I love it.

I'm not smart enough to follow some of these theorems. I do know that I've never had a problem with my gen 3 bars and vibes, but I run grip buddies all the time. I did put on big ass hvmp ends I bought from a forum member. No problems before or after. Then some guy tricked me into buying tech spec pads by throwing in color matched bar ends. Pads were for a different bike and were damaged. It was a Canada thing so I said- at least I'll try the bar ends. The ends were anodized aluminum. Much lighter than factory. A pound lighter than the hvmp. Supervibrationengage###. Put the hvmp's back on. No prob at any rpm. YMMV. Holla.

Vibration is your friend and lover on long, lonely rides.

Just wondering..

rushes said:

Maybe try filling the handlebars with Dyna beads?
Compared to most of my bikes current and past, the FJR is smooth as silk. I love it.

Click to expand...

I think Rushes might have something there, even though it was meant as a joke.A vibration damping material, other than metal, just might do the trick.

Maybe some silicon, injected into the handlebars, would work.

I guess I'm numb, because I have never felt this "buzz". Smooth fast acceleration that will rock your world. Who has time to worry about a vibe.