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Headshake... how to fix it?

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Hey guys,

I had a couple bad head shakes on my bike (05crf450) the other day and was wondering what can be done to fix it? It didnt seem to do it before, but maybe its time to change the fork oil, if that would even make a difference.

Thanks,Dave.

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steering damper is always nice, not sure about the fork oil. Try raising the fork tubes up in the clamps that seemed to help me.

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I have heard of guys tightening up their steering stem so as to cause a little drag on the bearings. They claim this helps. I am not so sure that this is a good idea as you may run the risk of damaging your bearings.

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I'm no expert and mean no disrespect but wouldn't raising the forks in the clamps be more likely to induce head shake? The bearings may need tightening to the specified setting as noted above.

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I've found three causes of head shake personally (sometimes painfully). First was too little race sag (fork angle too steep). Second was too much race sag (fork angle too shallow). Third was too much fork rebound damping combined with too little fork compression damping (fork packing - fork angle too steep). I'm sure there are other causes....

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I'm no expert and mean no disrespect but wouldn't raising the forks in the clamps be more likely to induce head shake? The bearings may need tightening to the specified setting as noted above.

Yes, it would turn quicker, but would be more likely to shake. Still dont think that is the problem. You gotta squeeze the bike with your legs.

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Yes, it would turn quicker, but would be more likely to shake. Still dont think that is the problem. You gotta squeeze the bike with your legs.

Kinda like squeezing a turd? :thumbsup:

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Kinda like squeezing a turd? :thumbsup:

:ride::applause::applause::applause::ride::applause:

If you're getting those kind of results, you may be squeezing a little too much!!!

Like skipn8r said, the ride sag would be the first thing I'd check....

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I hear people talk about head shake all the time, but I don’t think I have ever experienced it. Maybe I don’t notice it or don’t know what it is. I always assumed it was bad feed-back to the handle bars at high speed. What does your bike actual do when you get head shake?

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Usually the handlebars swap back and forth very fast and VERY violently from lock to lock. That usually happens for about 5 or 6 times, then the bike throws you to the ground with some serious force. My good buddy watched me do that on my old '02 450. He said the ground shook when I hit.

Your bike sets up a set of oscillating forces that become unstable and build on each successive swap until the point is reached where the bike wants to tear itself apart and you crash. It's a complex combination of frame geometry and suspension settings, speed, weight positioning, and terrain that can set this off.

I brought my case on when I jacked up my rear end with less sag and lowered my front end by raising the forks in the tripple clamps to fix the poor turning of my 450. It did turn better, but at the expense of stability through this slight downhill section full of braking bumps. I crashed like that a few times through there with that setup.

Chris.

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In that case, I don't think I have ever had head shake. I've swapped out on rough straight-aways but I don't think it had anything to do with the bike's steering. Thanks

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I have heard of guys tightening up their steering stem so as to cause a little drag on the bearings. They claim this helps. I am not so sure that this is a good idea as you may run the risk of damaging your bearings.

I use this method and it seems to really help . I read an article written by some pros mechanic and I guess it's common practice on the race circuit. Nowhere near as good as a stabilizer, but it definitely helps.

Chris

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If you raised your forks any,and if you haven`t check your sag,i would do that. Your sag such be 100 to 105 on a crf. Do you ride in soft, or sandy dirt? If so your front sould ride a little high.

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Maybe you need 49 front springs? Have you change you clickers?

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I've found three causes of head shake personally (sometimes painfully). First was too little race sag (fork angle too steep). Second was too much race sag (fork angle too shallow). Third was too much fork rebound damping combined with too little fork compression damping (fork packing - fork angle too steep). I'm sure there are other causes....

Hmmm... that's interesting on the fork tuning direction. I searched the suspension forum and the consensus on adjustments for headshake was:

a) for sure set the sag correctly

:thumbsup: add rebound damping in the forks

c) reduce compression damping in the forks.

For me, my sag is correct for the total but the initial sag is short as the stock spring needs more rate. Adding 3 clicks of rebound and taking away two clicks of compression on the forks makes the bike go thud instead of boing when coming up short on technical doubles. For high speed rough stuff, I find if I get too far forward, like when shifting standing up that headshake gets stupid. Flexing my knees and squeezing and getting back a little further makes it manageable.

I do know that adding fork compression and reducing rebound damping makes for silly headshake.

I've tightened my steering head bearings as far as I want to go but that seems to be minimally effective. Like skipn8r says, it's a dynamic effect that is difficult to 'turn off'.

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