| Author | Message | ||
     Jeremyh |
considering i now have about 4litres of coffee in me for the day i think i am feeling much better. ZZZZZZ......BBBBBBZZZZZZZBBB........BBB...ZZZZZ | ||
| Iamike |
Tramp- I agree with Jeremy. When someone asks a basic question, whether it be about bar ends or oil, it is best to be informative not prejudicial. This is especially important for new posters just trying to learn something. When I see smartass comments that aren't helpful I see that person as being childish. I avoid other boards exactlly for that reson. This one has fairly mature discussion of matters. I would guess that you are a super guy that is very knowledgeable, prove it by being helpful. | ||
| Tramp |
Iamike- did you READ my first response to the query? I said: "? just use 'great stuff' foam insulation-in-a-can." how the sam hill was THAT prejudicial? next, another poster claims that the product that I selflessly recommended will do "nothing" THAT is prejudicial. it's all there, just read the thread..... mike, i'm not here to "prove" anything... sometimes, being overly sensitive about what you consider to be "smartass" comments IS the definition of prejudice... you gotta relax, m'man!} (Message edited by tramp on August 11, 2005) | ||
| Bomber |
the board has teken a distinctly wintery feel of late (when many of us are suffering from PMS -- Parked Motorcyle Syndrome) -- not sure why this should be the case -- phase o the moon, alignment of the planets, the price of tea in china -- at the end of the day, it makes lil nevermind -- prhaps if we all took a deep breathe, figured everyone was attempting to be helpful/funny/charming (all in their own ways), it might lower the collective bile level a bit it's just motorsickles, folks -- signed swank leftie | ||
| Tramp |
at this point, after actually taking the time to post several disclaimers as to my typing style and peculiar humor, i've done all i can. if anyone's that deeply offended, time to take it up with the cat in the mirror. just a motorcycle, ladies! | ||
| Whodom |
Some of these threads have taken some weird turns lately... Hey Tramp, You did interest me enough to try some "Great Stuff" in my handlebars on my S3 this weekend. They're a little buzzy at certain speeds and I figure that's worth a try. You know, this is one of those things I'd REALLY like to see somebody do a scientific comparison test of. Everybody's got some theory for helping vibration; it would be good to hook up some kind of instrumentation to the handlebars on a bike and try a bunch of different things and see which could be shown to work best. Maybe we can talk Blake into doing it after the exhaust shootout.... | ||
| Tramp |
um...yeah.. i didn't just pull that one outta my keister, though. as i'm sure i stated above....it's worked for me and for many customers...for me it's NOT, as you say, a "theory". as far as instrumentation, well...what better instrumentation than your own two hands? at what point will you NEED to look at a thermometer to know that it's hot out, anyway? kinda scary.... good luck with the instrumentation, though....  (Message edited by tramp on August 12, 2005) | ||
| Whodom |
(waaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaayyyyyyyyto many 'engineers' here) Well, duh. This board is run by an engineer, Erik Buell is an engineer, I'm an engineer and there's a lot more. Yep, there's a whole bunch of us here.  Didn't mean to imply your suggestion came from a rectal databank. It's just that being an engineer, I have this natural tendency to ask "OK, it reduces vibration, but how much does it reduce vibration?, would a Barsnake work any better?, would big-arse bar ends work better?, etc. If engineers didn't think like that, there wouldn't be any Buells. | ||
| Wyckedflesh |
One of the bike mags, probably a UK mag as they seem to be more willing to research just such with "Home remedies" did just such a research, their "claim" was that having a heavier weight out at the ends of the bars countered the majority of vibration, based on the principle of leverage. They said it wouldn't counter all vibration, that some frequencies had such short wavelengths that it cycled way to often before it reached the weight. This was back in oh say 89/90/91 when it was all about the Sound of Singles racers in all the UK mags. | ||
| Whodom |
Wycked, thanks for that info. Wish I had the time and means to delve into this further. My gut feel is that adding mass to the bars, in the form of heavy bar ends, lead shot, or whatever does the most the quell major vibration. I suspect that adding some kind of soft stuff (foam, RTV silicone, a Barsnake) damps out "overtones" of the major resonances. The combination of the two may work best. Maybe Blake or one of the other M.E.'s here has more experience in vibration-related stuff and can chime in? (Sorry Tramp, bear with us...) | ||
| Bomber |
what's needed is a device to produce vibes equal to, but 180 degrees out of phse with, the vibes going into the frame/bars/pegs, yes? sorta kinda like the Bose noise cancelling headphones . . . . | ||
| Tramp |
no- hey- we all NEED to get as many experiences (and as few "opinions"  ) as possible. and, as you say, barends absolutely remedy most of the major, low-frequency judder. of course, one should stop and remember that such judder is a symptom of an eccentricity (literally) elsewhere, and it's NOT the fault of the bars. searching out and finding the cause (especially all you "hey- we don't need wheel balancing" guys) is the real fix. that being said, I was contrasting foam sealants and silicone caulking to the 'bar snake' ( bar snake- it's no longer just a guy in a polyester shirt and a pocketful of Roofies), to let the thread-poster know about an alternative to the item he mentioned. i love barends, i use 'em frequently (pun intended  ) but the thread inquiry wasn't about them. I mnore than agree= let's examine all experiences. too many academics here, anyway. now- lemme get back to the house i'm painting.... | ||
| Whodom |
Bomber, that probably would work. I read a while back Nissan had something similar in some of their autos- active panels attached to the roof that countered engine and road noise. Supposedly the car was quieter turned on than turned off! Hey, if you REALLY want to get funky, check these out: http://www.fasstco.com/html/flexx_bars.html For $299, they better work well. Of course, they do LOOK pretty cool.... | ||
| Bomber |
Oh, Noooooo -- I was funnin, Whodom (but you knew that, I'm sure) -- it's just a larger, more goldberg-esque take on the counterbalancer idea, afterall I'd heard of the Nissan work -- seems developing a new, quieter steel was cheaper (no surprise, there) those flexi bars make me a bit queezy, doncha ya know -- I'm sure they're trick and all, but I'm thinkin I got anough monkee motion going on with dealing with leaning, accelerating, the rotation of the earth, and my silly knees -- course, I DO want to keep my buttons at the Luddite meeting, so I sorta haveto say that, don't i? | ||
| Blake |
When it comes to vibration, handlebars are like cantelever beams. They get excited (vibrate badly) when the frequency of vibration at their base or mounting points equals their own natural frequency of vibration. Just like how a piano string will vibrate sympathetically when the right tuning fork is hit and held next to it. The fundamental natural frequency (fn) of vibration for any undamped system is governed by the following relationship: Where k is the stiffness of the supporting element, and m is the mass it is supporting. Since 1/2p will always be 1/(2*3.1416) = 0.159 and nothing we can do to the handlebars will change it, we can ignore that particular term in our quest to understand how various parameters affect the vibration of handle-bars. So what we are left with is the generic stiffness (k) of the handlebars and generic system mass (m). So if the fundamental natural frequency of vibration (fn) is proportional to the square root of (k/m) or SQRT(k/m) or (k/m)1/2, what can we identify that might alter the natural frequency, namely reduce it, so that it does not occur at a frequency that is irritating to our hands? If we want to lower the resulting ratio of two terms such as k/m, we can either decrease the numerator (top part of the ratio) or increase the denominator (bottom part of the ratio). I don't think we want to decreas the stiffness of the handlebars as that could make them weak and/or flimsy. But we can certainly increase their mass. The most effective and aesthetically pleasing way of increasing the mass of our hollow handlebars would be to fill them with something very dense, like lead and/or we could add some weighty bar-end sliders or bar-en mirrors. Filling the entire handle-bar with lead is a bit inefficient though since the lead needs to be nearest the poin at which the worst vibration occurs, namely near the hand-grips or ends of the handle-bars. Any lead located away from that area is of little effect and is just adding weight to your bike, a bad thing. Zat make sense? So maybe the ideal solution would be to fill the center of the handle-bars with foam then inject into the last 7 or 8 inches a lead shot and epoxy slurry (we need the lead shot to be solidly and firmly connected to or adhered to the handle-bars). Of course if you have bar-end hardware for sliders or mirrors, be sure to leave enough room for its installation. Then go out and buy some lightweight carbon fiber brake and clutch handles.  | ||
| Bigdaddy |
Squeeze 'em harder and once you go numb, to about the elbow, it's all good. Where's the Ironhead crew? Let's discuss some vibration :-) Greg | ||
| Tramp |
that made no sense to me, but i trust the inherent veracity of the statement | ||
| Blake |
I'll try to put it more simply.  Short of eliminating the source of vibration, adding weight at/near/to the ends of handlebars is the most effective way to quell the buzzing type vibration that can be irritating/numbing. | ||
| Whodom |
So, more mass and/or flimsier handlebar construction lowers the resonance frequency, and less mass and/or stiffer bar construction raises the resonance frequency, correct? Based on that, the Flexibars (see link above) should do a really good job of cutting vibration. | ||
| Aaomy |
from the iron head crew.. made my own 1" billet triple trees and angled the forks another 6 degrees just for fun. then i hard mounted the bars as a speedo.. you can tell exactly how many rpm and how fast you go by how hard it is to hold on. its insurance,, no joke you cant over rev the bike.. she simply vibrates you hands off the grips... ride my old girl a while and you wont even notice you buell running... besides im not worried about taking vibrations out of the s2t bars,, just the front of the seat..the nut juggler is fun to start but it gets really old on long trips...blake will the lead shot work for that... blake,, placed the shot in the area most affected,,ive swallowed about three pounds and i think its working,, i dont feel the vibration any more, but am seriously having a hard time getting the paint chip taste out of my mouth.. sorry about my twisted hummor.. have the liquid bar snake sitting on the dinning room table waiting to go into a friends 883.. will post back when we get it installed.. but that might be a while.. this may sound funny but my hands get more fatuiged and feel the vibration more off a 1" grip more than the 7/8" grips. i just got a set of the new harley reduced sized grips to try on the s2 from just holding them they really feel like the cats meow for 1" bars.. guess thats all the fun from this iron header... | ||
| Tramp |
sounds dead-on. i switched to an s3 frontend for my s2, primarily because of my hands' preference for the ergos of the smaller 7/8" bar. fatigue was part of that equation, as well | ||
| Mr_grumpy |
So, Having read this thread from end to end, if I've got the hang of this right, I can damp the frequency using lead shot & silicone implants, or cancel out the problem using a vibrator, Perhaps I'm on the wrong frequency here.  | ||
| Jackbequick |
"..it would be good to hook up some kind of instrumentation to the handlebars on a bike and try a bunch of different things..." This might work. Before I got a tach on my M2 I used to set the idle speed by watching a street light (it has to be at some distance) in one of the stock "mickey mouse" rear view mirrors. The engine vibrations caused the street light to create patterns as seen in the mirror that varied with engine speed. The pattern would go from a Lissajou pattern (horizontal figure 8) to a slightly elliptical circle as the engine speed went from 1,300 RPM to 1,100 RPM. The target RPM was 1,050 RPM and that was seen as a perfectly represented "O" or circle. As the engine speed dropped further, the circle would reduce in size. At 700 RPM (where low oil pressure starts to become a real danger to the engine) a erratically dancing dot was seen. Slowing the idle speed further would eventually produce a chilling silence and single large and steady dot of light. At this point you were seeing the reflection of a street light in a mirror because the engine had stopped and the mirror was absolutely free of vibration. So I'm thinking that studying these light patterns before and after a change in bar deadening material would let you evaluate the damping effectiveness. If anyone is still reading at this point, now is the time to laugh. :>  It is like an April Fool's joke. But I'm also thinking some one else has not read this far and is already working on a reply... Jack | ||
| Tramp |
jack- let me tell you something, you so and so... oh... it was a joke...  | ||
| Johnnylunchbox |
I sell bar end weights. I am not an engineer, but engineers designed the bar ends that I sell. Blake's explanantion seems to be in line with the laymen's explanation given to me by the engineers. I am not pushing my product here, and in fact I don't have any for the Buells yet. When I do I will promote them in keeping with the forum rules, and possibly take Blake's suggestion and approach a sponsor to carry them for me. They are not so much vibration dampers as they are resonant frequency changers. In my opinion you can add lead shot and/or caulk, but the net effect is so little relative to the amount of work involved. Engineers concur that more weight at the ends is better. I've even had reports that the added mass cures some minor headshake. Just my $0.02 Steve | ||
| Midknyte |
...I can damp the frequency using lead shot & silicone implants, or cancel out the problem using a vibrator... Having a vision of a pair of vibrators stuck in bar ends. A bad vision... | ||
| Gentleman_jon |
As usual, Blake's description of the mechanics of the vibration problem, are, as Court would say, "accurate". Here is a design solution to the problem that has proven satisfactory for the last 8000 miles or so on my 2003 XB9S, " Ol' Yaller". Essentially this is a device to redistrubute the frequency of the vibrations, and reduce their amplitude by converting them to heat . The lead bar adds considerable mass, ( about 12 oz. ) where it will do the most good, and lowers the resonant frequency of the handlebars. The mechanism is a 4"x1/2" lead bar, weighing about 6 ounces, wrapped in a 1/8" layer of soft Sorbothane, a viscoelastic material developed to absorb vibration. http://www.sorbothane.com/ In actual construction, several details were changed: 1. Threaded rod was omitted as the friction fit was adequate to hold the assembly in place. 2. The "carpal tunnel relief channel" was deemed unecessary, but I still think it is a good idea. This device, coupled with relearning to ride without gripping the bars too tightly has totally eliminated the numb hand problem I encountered when I first started riding this machine.  | ||
| Johnnylunchbox |
Gentleman Jon - I like your way of thinking. Your lead bar has the effect of changing the resonant frequency, and your sorbothane has the effect of a damper by converting the motion (vibration) to heat. Really nice, I like it. | ||
| Smitty808 |
Ok...not to confuse this conversation even more, but, what are the implications of putting say 12oz. right on the end of the handlebar of a motorcycle that makes so much cyclic resonance? Yes, it should throw the vibration into another frequency, which could put it into an RPM range that keep it from rearing it's ugly head, but if it does(rear it's ugly head), what are the chances that the extra weight will cause metal fatigue, causing the bars to crack at the pivot point of the vibration? I may be WAY off base here, because unlike everyone else...I'm not an engineer, but I have graduated from the school of hard knocks(much like Tramp). I have built several custom offroad, and racing vehicles, and have seen the effects of metal fatigue at work! Let me know if I am wrong...'cause the bar vibes are driving me nuts, and I am standing here with a tube of silicone caulk, and 4lbs of lead shot, awaiting your replies!  | ||
| Whodom |
Jon, Pretty cool design. How difficult was it to find 1/8" Sorbothane and 1/2" lead bar? I wonder if it would be practical (and desirable) to make hand grips out of Sorbothane? |
