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headshake

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Hey Guys,

I’ve got a 2006 S.

A problem has developed after swapping out my fork springs (for Racetech 5.0’s), and rear shock spring (for a Racetech 6.0) and adding a #1 Kouba Link. You guessed it---headshake. The faster I go, the more noticeable it becomes. (I'm talking on the street). I set my race sag standing on the pegs with all my riding gear on at 3.9 inches. I’ve been playing with the settings ever since. Since I ride in northern Michigan, most of the trails I face are sandy as hell, so I have to keep my compression clickers close to, if not maxed.

But at times, when I do jaunts on the highways, the headshake is formidable.

BTW, I slid the front fork tubes up in the triple clamp about ¾ in. (One of the first things I did when I bought it.) That’s why I felt okay to put the Kouba Link on the rear to compensate afterward.

Any ideas would be appreciated.

Thanks!

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you need to back out your rebound adjuster up front until the problem goes away, and it will :thumbsup:

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Drop the fork back and get a scott's :thumbsup:

Are you sure that the oil level is the same in both fork legs? Are the settings the same?

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Yeah, I hear ya BassMan.

I turned up the rebound damping while I was experimenting in the sandy trails I ride and noticed a huge improvement in that area. But my high speed pavement control is now suffering for it. It's like going from one extreme condition to the other. Guess I'm trying to get the best of both worlds....

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Yep, I kept the oil level the same and double-checked the clickers to make sure they're the same--still the shake persists. I have to push forward hard on the grips to keep the bars from shaking slightly starting at about 65mph, and vigorously at my top speed of 91mph.

What's a Scott's?

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Yep, front and rear have both been lowered about 3/4 in., did that to keep the frame geometry the same.

Yes that would have kept the frame geometry the same, except that you changed the springs as well.

So now you have altered the ride hight because the race sag has changed, mainly at the front, which is non adjustable.

I had the same trouble with mine, I fitted a custom rear shock with stronger spring to lower the bike by 50-mm, I also fitted a set of progressive front springs and shortened the forks by 50-mm to match the rear.

I had to play about with the pre-load on the front to get rid of the same wobble.

Specs for the changes to the suspension is listed in my garage.

Neil.

:thumbsup::ride::cry:

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Unfortunately, the problem lies in the design (geometry) of the DRZ. It is a "dirtbike" designed for offroad use mainly, and what works offroad, is not going to work as well on the street and vice versa. Put the forks back where they were from the factory. Adjust the rebound and get a GPR stabilizer. You will get better customer service with GPR. The GPR dampens both ways, unlike the Scotts that does not dampen back to center. The Scotts a reputable product but I think the GPR would do a better job of controlling headshake on the highway (just a theory). I have a GPR on my KTM and it is a lifesaver on the trail.

The worst thing you can do is put on aggresive knobby tires (esp. on the front). If you are going to ride on the street, anything more aggressive that a Pirelli MT21 will affect stability. If you gear it down, buy a longer chain so that you maintain the stock wheelbase. I've tried all these different things and they make difference in handling. I've learn a few things with my 2006 DRZ:

http://www.thumpertalk.com/forum/showthread.php?t=389445

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Yep, I kept the oil level the same and double-checked the clickers to make sure they're the same--still the shake persists. I have to push forward hard on the grips to keep the bars from shaking slightly starting at about 65mph, and vigorously at my top speed of 91mph.

What's a Scott's?

This is a scott's.

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Unfortunately, the problem lies in the design (geometry) of the DRZ. It is a "dirtbike" designed for offroad use mainly, and what works offroad, is not going to work as well on the street and vice versa. Put the forks back where they were from the factory. Adjust the rebound and get a GPR stabilizer. You will get better customer service with GPR. The GPR dampens both ways, unlike the Scotts that does not dampen back to center. The Scotts a reputable product but I think the GPR would do a better job of controlling headshake on the highway (just a theory). I have a GPR on my KTM and it is a lifesaver on the trail.

The worst thing you can do is put on aggresive knobby tires (esp. on the front). If you are going to ride on the street, anything more aggressive that a Pirelli MT21 will affect stability. If you gear it down, buy a longer chain so that you maintain the stock wheelbase. I've tried all these different things and they make difference in handling. I've learn a few things with my 2006 DRZ:

http://www.thumpertalk.com/forum/showthread.php?t=389445

Scott's dirt bike dampers work on the away from center only to make it easier to negotiate tight trails, their street ones dampen both directions.

Scott's is also a good company to work with.

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All,

Thanks for the tips you guys! I'm going to start with the simplest one (backing off the rebound in the front) and then I'll go from there (onward and upward to the more expensive ones). Just have to wait till I get up north for the w/e and I'll begin experimenting.

BTW, all the changes were made do to my physical specs: 6 ft tall, 230lbs, 31 in inseam. (Which is also why I went with the gel seat.) The whole idea was to gain better control over the S, which I have grown very fond of. Beacause of this, I doubt I'll slip the tubes back down in the forks which may solve this problem but put me back to square one.

Take care guys and thanks again!

Swerve3964 :thumbsup:

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