GStwin.com GS500 Message Forum

Main Area => General GS500 Discussion => Topic started by: Travis on October 04, 2004, 08:46:45 PM

Title: Bar Shake
Post by: Travis on October 04, 2004, 08:46:45 PM
I have noticed that 50 mph and above if I take my hands off the bars the bike will get a very uncomfortable shake. Is this common in the GS or does this mean something is bent or the wheel is out of balance? The only other bike I have rode that does this is my friends 98 ninja 500, but the CBRs and GSXRs I have rode dont do this, what gives?
Title: Bar Shake
Post by: Kerry on October 04, 2004, 10:19:32 PM
The first thing to check is the air pressure in your tire.  It's amazing the difference a few pounds-per-square-inch can make.

If that's not it then we can dig up some checks for unwanted "play" in your steering head, etc.

PS - Check both tires while you're at it.  Then try a Search for "head shake" and similar phrases.
Title: Bar Shake
Post by: Blueknyt on October 04, 2004, 11:46:35 PM
check rear wheel alignment, bad bearings, bad or loose headstock bearings, bent rim/s, Missadjusted fork hieghts in clamps. bent frame, bad swingarm bearings. miss shapen tire.
Title: Bar Shake
Post by: Travis on October 05, 2004, 06:51:22 AM
Ok later today I will check my tires and jack it up and check the bearings, but one of my friends just bought a new GS and I noticed it had bar ends. Mine dosent have these does it make a differance?
Title: Bar Shake
Post by: Kerry on October 05, 2004, 09:20:32 AM
Bar ends may cut down on high-frequency vibration ("buzz") in the bars themselves, but they wouldn't prevent (or cause) head shake.
Title: Bar Shake
Post by: slotcar on October 05, 2004, 09:33:56 AM
I noticed the same shake or shimmy in my '96 GS500E when I bought it a month ago.  I replaced the stock fork springs with a Progressive spring set and it dissapeared, except at 41-43mph. I am hoping when I get new tires it will go away completely.
Title: Bar Shake
Post by: sprint_9 on October 05, 2004, 12:02:55 PM
Its the bar ends, I broke one of my screws and had to take mine off and since Ive taken them off I have had a very violent shake when I take my hands off the bars now, first time it did it I thought I was done for.  Id try some bar ends before I tore into the bike.
Title: Bar Shake
Post by: Travis on October 05, 2004, 01:31:18 PM
That sounds like my bike where is a good place to get some bar ends I went to the dealer today and they just had them for gsxrs.
Title: Bar Shake
Post by: Kerry on October 05, 2004, 01:45:04 PM
Quote from: sprint_9Its the bar ends, I broke one of my screws and had to take mine off and since Ive taken them off I have had a very violent shake when I take my hands off the bars now, first time it did it I thought I was done for.  Id try some bar ends before I tore into the bike.
Hmmm.  Lots of folks ride without bar ends, even though it's usually not by choice.

The bad shake after removing the bar end(s) could have been just a coincidence rather than a cause-and-effect situation.  I'd keep looking for other possible causes.

I wonder what your tire pressure is like?  :dunno:
Title: Bar Shake
Post by: slotcar on October 05, 2004, 01:52:39 PM
I forgot to mention that when I first got the bike it did not have bar ends. I added them when I put in the new springs. Like I said earlier the improvement was noticed.
Title: Bar Shake
Post by: sprint_9 on October 05, 2004, 06:35:37 PM
I still say its bar ends, it doesnt do it everytime you take your hand off the bars but on certain occasions where the load on the front wheel is just right it just goes like hell, needless to say it gets your attention real quick.

For some bar ends maybe check around the for sale page, there have been a couple of bikes being parted out as of late you might be able to find something there.
Title: Bar Shake
Post by: Travis on October 05, 2004, 08:07:18 PM
Ok I just checked my tire pressure and the front was 20 pounds. That seems low to me so I will fill it up to specs and see if it gets any better.
Title: Bar Shake
Post by: John Bates on October 05, 2004, 08:28:12 PM
Quote from: Travis....... front was 20 pounds. That seems low to me ........

You bet it's low. Should be 33.

My 92E doesn't have bar ends and I don't feel any shake, just a slight buzz.

Then again, I haven't taken my hands off the handlebars either. :nono:
Title: Bar Shake
Post by: Kerry on October 05, 2004, 09:24:52 PM
Quote from: TravisOk I just checked my tire pressure and the front was 20 pounds.
We have a winnah!

(But be sure to let us know what you think AFTER you get the tires pumped up to 33 psi....)
Title: Bar Shake
Post by: jake42 on October 05, 2004, 09:26:54 PM
mine's always had a nasty headshake between 40-50mph.  drives me crazy and is even worse now with the shorter drag bars on it.  I'm pretty sure mine is due to worn headstock bearings because i played with tightening them and now i get this weird pull to one side at really low speeds too like i simply moved the bad bearing around int he race.  The sad part is that I have the new headstock bearings sitting in my basement, just havent' had time to put them in yet.

Jake
Title: Bar Shake
Post by: robo on October 05, 2004, 09:40:49 PM
Ever since i installed my clip ons, i havent gotten my bar ends on and i know they vibrate really hard. Hands start to tingle after half an hour of straight riding. But if i double up my gloves (i wear motox gloves) i can go much longer. I like it though, its nice and massaging  :cheers:
Title: Bar Shake
Post by: Blueknyt on October 06, 2004, 01:11:53 AM
the bar ends add alittle weight at the end of the bars only to absorbe vibration, they will NOT stop or be the starting Cause of a tankslapper.

it will always boil down to how the tires track, front to back, as well as cintrifical plane (for lack of a better deffinition) worn beraings in wheels, and swingarm will change the way the wheels are oriented on all axis.

head stock (steering neck bearings) may have a flat spot just off center of the Thrust line which may keep the front wheel turned just a touch. giving the effect of the bum front wheel of a shopping cart.

Tire pressure will change the shape of contact patch where the tire meets the pavment.
Title: Bar Shake
Post by: scratch on October 06, 2004, 07:55:43 AM
Remember when I crashed?



Check your suspension. Sag to be specific. You should have no more than 7/8 inch static sag.
Title: Bar Shake
Post by: scratch on October 06, 2004, 07:58:59 AM
Check your suspension, too. Sag to be specific. You should have no more than 7/8 inch static sag. Too much sag causes the steering angle to be steeper, which reduces trail and the castor wheel effect of the wheel tracking in the direction that it's going.
Title: Bar Shake
Post by: Travis on October 07, 2004, 05:58:14 PM
Ok I just aired the front tire up and went for a quick ride. The bike turned in much better but the shaking was still there but only when I let off the throttle. I didnt get to ride long enough to see if it would shake at 55 but while accelerating to 55 and staying there for a few seconds there was no shake but as soon as I let go there it was and the bike was in 5th gear so it slowed down kind of quick.
Title: Bar Shake
Post by: sprint_9 on October 07, 2004, 06:33:02 PM
Put bar ends on it, I would bet that it would cure your problem.
Title: Bar Shake
Post by: charleym3 on October 07, 2004, 07:11:59 PM
Why exactly are you letting go of the bar at 55+ MPH?  It sounds like the problem you're having is harmonic vibration rather than real buzz.  Harmonics is/are what makes a bell ring.  If you do something to dampen the vibration, like, say, hold onto the grips, it will dampen the harmonics.  Adding bar ends changes the harmonics and dampens the vibration.  
I used to have an 86 Chevy Cavalier Wagon.  Old style radio antena.  At 58 MPH wind speed, there was a harmonic vibration and the wave length was the same as the length of the antenna.  Up to about 66 MPH the wave length got shorter and shorter until the secondary harmonics killed the standing wave pattern.  Intersting to see a real world application of what I learned in tech school, but I digress.  
If you alter the harmonics you can kill the vibration.  Bar ends will help.  A bar-snake might just fix it for good.  Worth a look.  

Hey Kerry, do any bikes still suffer from high-speed-wobble.  I went down from that once.
Title: Bar Shake
Post by: jake42 on October 07, 2004, 07:17:35 PM
tire pressure is your friend.  after reading and replying to this post i decided  I should check mine and the front was down to about 25.  bike felt so much better today to and from work that i could get it leaned over nice in my favorite twisties that i make a point to ride on every day.

Jake
Title: Bar Shake
Post by: Travis on October 07, 2004, 08:40:12 PM
My left arm is messed up from my job but to make a long story short Im left handed and riding for a while will make my hand go numb and I let go to streach my and rest my hand on the tank. Now riding with one hand I can feel the vibration and if I let ease up on my grip it starts to shake. I am getting my problem treated now and while Im off I want to get my bikes too. Everything on the bike seems smooth so I hope the bar ends will help because the short ride I took with the air pressure change made a noticable differance. Also my bars are bent on the right side just enough to hit the tank would this make a differance?
Title: Bar Shake
Post by: Blueknyt on October 08, 2004, 12:21:56 AM
i have no bar weights on my bars, infact, i have lightweight clipons instead, and my front end doesnt shake, no matter what speed.  weight will SLOW the wobble as it takes energy to wobble. but will not stop the cause. your right about harmonics but in this case its applied BIKE WIDE, bearings, frame flex, tirepressure, spring load, dampining of shocks/forks,rubber,weght placement, and overall geometry
everything on the bike and how it interacts with its fellow parts has pull, or stores and releases pull.  when everything is right, these pulls ballence out, when something is out of wack, the pulls become no longer ballence and you have wobbles.   some little some extreme.
Title: Bar Shake
Post by: slotcar on October 08, 2004, 10:06:53 AM
It sounds like this "shimmy and shake" may be inherent in the GS500. Minor in some bikes and more pronounced in others.
Title: Bar Shake
Post by: charleym3 on October 08, 2004, 10:31:35 AM
It's inherent in all bikes.  The longer bars can amplify the effect.  Substantial bends in the bars can help reduce the effect.