Head-shake at High speed

[kiwikx500]

Running 14 lb on both Tires, felt lot of vibration through hand grips at high speed in a straight line (flat shingle road) and their was head-shake - could feel like the front wheel tracking left to right.

Had the tyre swapped around on the rim to get more life out of it and hub respoked.

Can the brake dragging cause this ? Pretty sure bearing looked and went back in ok.

Any pointers please to steer me in the right direction ?

Cheerz

Kiwi

[KXcam22]

Try experimenting with your front fork clickers.  Sometime too much compression can make the front end nervous. Cam.

[bigbellybob]

I'm not saying this is the problem but setting the sag makes a big difference.

Can the brake dragging cause this

most definitely if the front brake is dragging. i had this happen the front master was holding pressure after releasing the brake. i dumped it 3 times before realizing the front brake was dragging. the front end was all over the place and it was scary. if the brake is dragging fix that first.

[Hillclimb#42]

 I wonder about off set fork set up. That is, in my own personal experience, I get nervous about fixing one fork seal and not the other. Then the sides would have different compression and rebound than the other side. Then I wonder how to be sure they are the same right now. Tighten the adjustment all the way and count the turns to make them the same turns back out?
  Then also have to mention not one of my bikes and my teammate's bikes,8 in all, have a perfectly balanced wheel. We wash them on a stand and use the pressure washer to spin and clean the wheel and that gets the whole bike moving on the stand. The guy I have mount tires for me has another guy lacing and truing wheels all the time. Front wheels do get all wobbily easy. I never seem to notice because of bumpy riding conditions. But I imagine flat out on whatever a shingle road is, would be shakin'.
  Could be the tire. how fast are you riding 50?60?

[bigbellybob]

Then the sides would have different compression and rebound than the other side.

this is not a problem on my bike one leg dose compression only and the other leg dose rebound only.
if the front brake is dragging that's a problem. the front end will be all over the place its a very weird feeling. its not like normal head shake or speed wobbles, the front end tracks funny and almost seems like the rear end is trying to pass the front end.

[don46]

out of balance suspension will cause this, back to stiff front to soft, changes the rake and can cause head shake. The K5 doesn't typically head shake if set up properly, are you forks pulled up in the clamps? they turn better but then you can get head shake. The CR 500 is pretty bad due to the steering head rake. I would take big belly bobs advice and set the rear sag, more than likely thats the culprit.

another trick that was used for high speed riding was to tighten the steering stem nuts a bit tighter to cause a modest amount of drag, that helped, and of course you can always get a steering damper.

[Hillclimb#42]

this is not a problem on my bike one leg dose compression only and the other leg dose rebound only.
[/quote]
  I had no idea you could do that. Is there other benefits other than not worrying about what I had mentioned about problems with an imbalance?

[BDI]

Head shake is usually caused by improperly set rear sag, coupled with loose head bearings. Get the head torqued right and set the sag correctly and I would be very surprised to see it head shake. When ever I go test suspension that is the first two things I do. With the suspension settings way off and out of balance.  I have had bikes do all kinds of scary crap but not head shake.

[don46]

you can't do what big belly bob describes unless you change to WP forks, KYB has both comp and rebound. I wouldn't worry to much about not getting the forks equal, as long as you know what the oil level was before leakage you'd be good to go. On the other hand usually when one starts to leak, then the other will shortly.

[kiwikx500]

Plenty of things to try  cheers

Probably as usual last thing I've done 

For the first time in years I "burbed" the front folks by removing the two brass screws up top to let any air that may have built up, don't think that is the problem but thought would mention.

Never felt this head shake before, probably doing 70 - 80 MPH. I'll whip the front wheel off and re-install make sure lined up and brake a ok.

If problem not fixed was thinking of going to Firestone and have wheel balanced - is it a done thing ?

[kiwikx500]

Cheers, I'll have a good check for leaks. The headshake not tank slapping stage but definitely not sure footed.

[barryadam]

Not sure about Firestone, but any motorcycle street tire installer can do a dynamic balance.  It takes a lot of weight to counter the rim lock, but it is MUCH smoother especially at those speeds.
When I first got the bike, they were not balanced and after feeling that high speed vibration, I immediatley had both front and rear done.
Make sure to check to see if the rims are running true, as well.

[Danger4u2]

I balance all my bike wheels, it makes a big difference.  It takes many weights to counter the rim lock.

[kiwikx500]

Cheerz guys for "The heads up" Good info 

[Albertan]

I agree with the earlier comments about too much compression damping causing headshake.  Also, if you have less sag and the forks pulled up in the clamps (I run 95mm sag and forks 10mm up in the clamps at the motocross track to help it turn), but on fast trails and rocks, it will shake.  For open/desert stuff, more sag at the back (105mm) and the forks flush with the triple clamps makes it more stable (but a little harder to turn).