Handlebar wobble

I'm hoping this is a real quick question to have answered, but we'll see.

    Like I said in a previous post, I recently bought a 1987 Kawasaki EX 500.  One thing I've noticed is that if I remove pressure from the handlebars when riding (like if I go no-handed), the bars start to wobble and it get worse in an exponential manner; as in if I leave my hands off the bars for more than 5 seconds, I'm done for.  Now here's the thing, if there is a lot of back-pressure happening (enging braking) the bike rides true.  Also, if I have one or both hands on the bars, there is no wobble.  I'm not sure if this is a speed-dependant problem, or an engine speed dependant problem.  I say this because as I downshift to slow down, I can remove my hands, but once the bike slows down (I haven't figured out the speed or rev speed yet), the wobble starts.  My first thought was that perhaps my forks are a bit twisted, or the wheels aren't properly weighted.

    Any ideas?  Thanks!  

I think every bike I've riden has been like that. My R6 is quite bad(too many wheelies). It's normal as far as I'm concerned.The way I see it , as long as it's stable with at least one hand , you're good to go.When do you need to ride hands-free anyways?  

If your getting head shake when just riding then you have an issue with the bike. You said it's an 87 ex500 so I'm guessing there are quite a few miles on it. I would first check the suspension settings it sounds like it might be sagging in the rear. If the bike has to much rear sag it takes weight off the front which can cause head shake. Try raising the rear and going for a ride. If this fixes the problem then your good to go if not then check the steering head bearings and make sure everything is ok in there. You might have to play around with the suspension to get that head shake to go away but that would be a good place to start. You will want to also check the compression and rebound settings, I'm not sure that a good setting for that bike would be but there might be something on this website that could point you in the right direction.  

What kawi6rr said is all correct.  However, all bikes have a steering wobble at some point.  It's usually speed dependant even though other variables such as rider size, suspension settings, and tire condition can play a role (road condition as well).  No bike has perfect geometry therefore all will do this at some point.  In addition to what kawi6rr recommended I'd also check the fork oil to make sure they have the correct amount of oil and equal amounts of oil in them.  There aren't many suspension adjustments on the EX500 so hopefully this is either the normal wobble or something that can be easily fixed.

One way to tell if this is a normal wobble or a bad wobble is whether or not you can feel it in the bars when holding on.  If you can't feel it in the bars it's probably the natural wobble that occurrs and goes unnoticed.  If you can feel the bar wobbling while holding on there's defenitely something wrong.  

It's the head bearings. If you haven't taken a front end apart before, your in for a treat.  

What everyone has stated above is true.  For those who do alot of wheelies, the steering head bearing will deterioratee over time (impact crushes one side of the bearing race).  

Your bike could just be suffering from parts settling over time and the head bearing just needs to be tightened (not too much though, just enough to snug the unit up).  

One thing that has not been mentioned here and is a common thing is this, how old are your tires?  Check the condition of your tires.  If they hav more than 3500 mile on them, the left side of the tires are probably "Cupped".  This is a phenomenon that occurrs because of the slope of the average road.  The center of each roadway is domed and slopes downward at the edges.  It is only a slight gadient but there none the less.  Over time riding at this off camber angle, the left side of motorcycle tires will "Feather" or cup.  This can also be the cause of your wobble.  

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What kawi6rr said is all correct.  However, all bikes have a steering wobble at some point.  It's usually speed dependant even though other variables such as rider size, suspension settings, and tire condition can play a role (road condition as well).  No bike has perfect geometry therefore all will do this at some point.

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Head bearing or Head bearing nut loose.
Check steering head. Get a stabilizer if it annoys you too much.  

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What everyone has stated above is true.  For those who do alot of wheelies, the steering head bearing will deterioratee over time (impact crushes one side of the bearing race).  

Your bike could just be suffering from parts settling over time and the head bearing just needs to be tightened (not too much though, just enough to snug the unit up).  

One thing that has not been mentioned here and is a common thing is this, how old are your tires?  Check the condition of your tires.  If they hav more than 3500 mile on them, the left side of the tires are probably "Cupped".  This is a phenomenon that occurrs because of the slope of the average road.  The center of each roadway is domed and slopes downward at the edges.  It is only a slight gadient but there none the less.  Over time riding at this off camber angle, the left side of motorcycle tires will "Feather" or cup.  This can also be the cause of your wobble.

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I have a zx 14 2007 at 139 mph and above the handelbars start to wobble and i am holding on when this happens.
i am on new road and old road an same thing .
what gives do i need to take the new front tyre back he balenced it and installed it for me.
I have a shinko 55 on the back and a dunlop stock on the front not lowered and rebound and compressin are set to stock.
This just started and i just turned 9000 miles on it  i ride all year long and it seemes the new front tyre is the culprit.
is the head bearings loose.?
the dont seem loose.
and no damper but was looking at an olind scotts damper.
it diddnt need a damper before so i think somethings shady.
i do no wheelies and no endoes   I do knee dragging and high spees road racing.
Please help
Dave.
e mail me  

A couple of suggestions:

For starters, the fact that you have different brand tires front and rear isn't a good thing. Different tire companies use different construction methods and materials in the carcass, and that can easily affect high-speed stability.

Also, with some bikes, replacing one tire while the other has some wear on it will produce handling anomalies. If there is any flat spot worn in the profile (especially the rear tire), it can affect straight-line stability.

Have you checked your tire pressures lately?

Hope that helps.