What Causes Headshake?


29 replies to this topic
  • motodude42

Posted February 15, 2005 - 04:19 PM

#1

I am getting some pretty serious headshake at high speeds (top of 4th gear)
on a semi-bumpy trails. The bike does fine in the whoops. I weigh in at 150lbs. fully loaded with gear. I have backed off the compression on the forks 4 clicks and went up and down on the rebound a couple of clicks. My sag is set up at 3.5 inches. Where do I go from here? I am coming off of a YZ250F and maybe my riding style needs to change. (Get over the bars more?) :) I know the ultimate idea would be a stabilizer, but... :) I don't want to ask the wife for that kind of cash. :p And yes, I wear the pants in the family. Just ask me. :D

  • DesertWR

Posted February 15, 2005 - 04:32 PM

#2

I would check your triple clamps and steering stem to ensure everything is tight. If that stuff is OK then your fork might be too stiff or the rebound too slow. The rebound in the 05's I just don't like. I put in RaceTech Gold Valves and a GPR and LOVE IT : :) :) Try adjusting the softening compression and/or speeding up rebound.

  • wr250rr

Posted February 15, 2005 - 05:24 PM

#3

Also make sure your axel is not toeing in your forks.
Before tighting the pinch bolts on the forks, hammer a screwdriver in between the slit after you tighten the axel nut.

  • Seabass

Posted February 15, 2005 - 05:50 PM

#4

Headshake is often caused by my wife asking me stupid questions

  • ckulzer

Posted February 16, 2005 - 07:35 AM

#5

Headshake could also be caused by a lack of trail. Have you messed with front end ride height? Try sliding the forks down in the clamp to increase trail or lowering the rear.

Increasing rebound in the front and decreasing compression will make the front ride lower. I would set the fork back to default and make those adjustments on the rear to see the effect. Perhaps backing preload off and letting the rear settle down into the stroke would be good to try too.

My '03 has always been "lively" in the front and I ended up with a WER damper.

Ride fast-take chances.

Chad

  • BubZ

Posted February 16, 2005 - 09:13 AM

#6

I used to get some serious headshake by drinking too much coffee after a nights drinking!! I have since overcome it by giving up the nights drinking and retaining the coffee.

Hope this helps.

Bud

  • motodude42

Posted February 16, 2005 - 02:09 PM

#7

Thanks for the jokes :) and replies. I have not touched the fork height in the clamps from stock. They are all the way down in the clamps. Should I try dropping them 5mm. or just increase rebound? :)

  • TeamScream

Posted February 16, 2005 - 09:11 PM

#8

you should try everything, but only 1 thinkg at a time, that way you can ride it and see what difference each adjustment makes.
Trial and error

  • mikedabike

Posted February 16, 2005 - 09:26 PM

#9

Why 3.5 inches of sag? Most people I know run between 95 to 105MM or about 4 inches. With the rear set that high it may be contributing to headshake.

  • motodude42

Posted February 17, 2005 - 06:52 AM

#10

I will give it all a try this weekend. I will let you know what I find out. Hopefully I can get this figured out, Scares the crud out of me when the bars have a mind of their own. :) Thanks for the help.

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  • Dan_from_HB

Posted February 17, 2005 - 07:10 PM

#11

Make sure damping adjustments are same on both fork legs, lighten up on the rebound up front, and give yourself a little more sag in the rear (assuming you measured it correctly). At only 150 lbs, you may have a little too much spring, or just a little too much preload in the rear.
Assuming everything's properly tightened, headshake usually comes from a steep steering angle. It's either designed that way (the WR and YZ are not), your ride height in the rear is too high (which tips up the fork angle), or ride height in front is too low (similar effect).
Honda CR's have a little steeper fork angle than WR's and YZ's, and they tend to exhibit a little more headshake. But it's not a trait common to Yamahas that are set up properly.
Good luck, and I would take it easy after making adjustments until you are comfortable that it hasn't made things worse.

  • motodude42

Posted February 18, 2005 - 09:50 AM

#12

Thanks Dan. I will measure my sag again and try these things this weekend. :)

  • dezdog

Posted February 18, 2005 - 03:05 PM

#13

My first trip out on my 05 wr450 I got the worst head shake ever when I was wide open and had to change my shorts! I installed my GPR dampner and have never had it again. Tell your wife its going to save your life. It will be the best money you will spend on that bike.
Dezdog
05 wr450 with the A.T.S.package

  • motodude42

Posted February 18, 2005 - 03:37 PM

#14

Where did you get the stabilizer and how much was it? :)

  • dezdog

Posted February 18, 2005 - 04:33 PM

#15

I don't remember exactly what I paid but you can check them out at www.gprstabilizer.com. I actually took the stabilizer off of my xr 650 that I sold, so I just had to by the new mount for the different top clamp. Good luck!
Dezdog
05 wr450 with the A.T.S. package

  • motodude42

Posted February 19, 2005 - 07:24 AM

#16

Thanks dezdog. Do you have to weld to the frame?

  • justarider

Posted February 19, 2005 - 07:49 AM

#17

Another thing you might want to look into is balancing your front wheel (and rear while at it.) The suspension settings are important as is all the things mentioned. I didn't see anyone mention tire balance. Some tires I've used seem to be slightly more prone to headshake than others. Alot of the time when I get headshake it's because I am not properly positioned on the bike. I'm sitting, relaxing and on a fast washboard crusing or slight decel. When up on the bike "riding" it I rarely get headshake. The couple times I've "fought" headshake, the front wheel balance was pretty far out and balancing the wheels helped smooth out things. There are steering stabilizers and alot of people use them. They do make long rides more comfortable for some. There are pro's and cons to steering stabilizers. If you opt for one definitely have a professional install it. The "pin" or pickup on the frame needs to be professionally tig welded. Some stabilizers have clamp on pins or drill\bolt arrangements that can come lose. Wheel balance is frequently overlooked on dirtbikes because most are ridden at speeds where a slight imbalance isn't noticed. The faster you go, the more noticeable the imbalance. Good luck with it and hope this helps.

  • dezdog

Posted February 19, 2005 - 09:12 AM

#18

If you use a stabilizer it doesn't matter if your wheel is out of balance.You have less fatigue and less arm pump which means more control. I have been using the bolt on style for five years and it works awesome, and is very simple to put on. I also race district 37 "desert racing" and the majority of everyone out there has a bolt on stabilizer and don't have any problems with them. In the sand you track straighter, if you hit a rock with your front wheel it wont rip the bars out of your hands,and it is more relaxing in the woops. I prefer the GPR over the scotts because of the customer service. They are out at every race and they support the desert riders.
Dezdog
05 wr450 with the A.T.S. package!

  • qadsan

Posted February 19, 2005 - 01:31 PM

#19

A stabilizer may cover up / compensate for the headshake issues, but I'd get to the root of the problem first and fix it before considering a stabilizer.

  • motodude42

Posted February 19, 2005 - 05:25 PM

#20

I agree. I'll figure it out. :)




 
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