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SPEED WOBBLE. I need to figure out why this happened so I can make sure it doesn't happen again.
SITUATION: Riding out on camping trip, heavily loaded, fairly wide rear soft panniers clinched tight against a hard pannier rack, front tank side panniers probably 12 pounds each, tank bag 10-12 pounds, Duffel bag strapped to back top plate medium weight, brand new tires and heavy duty tubes inflated to 35psi(Kendra k270's), full 5 gal gas tank, I weigh 265 pounds, this is on a 1994 KLR 650 stock. Had a fender bag on front with tools in it.

On a long flat straightaway I accelerate fairly rapidly up to 80 MPH(thought something on Carb stuck thought I'd try this to clear it out). All of a sudden the bike starts violently shaking from side to side both front and back and was getting worse quickly. I let of the throttle gently and was able to ride it out, but at the time I was sure I was going down. I don't recall exactly but I may have let off the throttle out of the acceleration right before the wobble started.

Can you give me your experience with this and help me figure out why this happened?

Thanks,
T33
 

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SPEED WOBBLE. I need to figure out why this happened so I can make sure it doesn't happen again.
SITUATION: Riding out on camping trip, heavily loaded, fairly wide rear soft panniers clinched tight against a hard pannier rack, front tank side panniers probably 12 pounds each, tank bag 10-12 pounds, Duffel bag strapped to back top plate medium weight, brand new tires and heavy duty tubes inflated to 35psi(Kendra k270's), full 5 gal gas tank, I weigh 265 pounds, this is on a 1994 KLR 650 stock. Had a fender bag on front with tools in it.

On a long flat straightaway I accelerate fairly rapidly up to 80 MPH(thought something on Carb stuck thought I'd try this to clear it out). All of a sudden the bike starts violently shaking from side to side both front and back and was getting worse quickly. I let of the throttle gently and was able to ride it out, but at the time I was sure I was going down. I don't recall exactly but I may have let off the throttle out of the acceleration right before the wobble started.

Can you give me your experience with this and help me figure out why this happened?

Thanks,
T33
Load imbalance that you happened to cause constructive oscillation at that speed.

Steering bearing is starting to fail.

Those are two guesses with the limited information
 

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Congrats on surviving.

A, get rid of at least half the load on the tank. It's too much weight, too far forward causing the overly soft front end to ride even lower, steepening the head angle.
B, don't chop throttle, as the front will squat, steepening the head angle and further exaggerating the problem. If you can, slide back in the seat to unload the front and slacken the head angle.
C, clamp the knees on the tank HARD, and loosen up on the handlebars, the bike WANTS to go straight. In the aviation world, it's called PIO (Pilot Induced Oscillation). You are consciously or unconsciously trying to correct, and using too much input, which sets it off the other way.
 

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Congrats on surviving.

A, get rid of at least half the load on the tank. It's too much weight, too far forward causing the overly soft front end to ride even lower, steepening the head angle.
B, don't chop throttle, as the front will squat, steepening the head angle and further exaggerating the problem. If you can, slide back in the seat to unload the front and slacken the head angle.
C, clamp the knees on the tank HARD, and loosen up on the handlebars, the bike WANTS to go straight. In the aviation world, it's called PIO (Pilot Induced Oscillation). You are consciously or unconsciously trying to correct, and using too much input, which sets it off the other way.
Thanks - good post. I experienced a mild episode of this in my first week of owning a KLR and wondered about this.
 

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Similarly loaded it happened to me also, not bad but enough to scare the s**t out of me. Something about the geometry / suspension I can't define. I simply slow down loaded like that.
 

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Stock syspension loaded down too much in the rear.
 

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Discussion Starter #9
weight forward

Congrats on surviving.

A, get rid of at least half the load on the tank. It's too much weight, too far forward causing the overly soft front end to ride even lower, steepening the head angle.
B, don't chop throttle, as the front will squat, steepening the head angle and further exaggerating the problem. If you can, slide back in the seat to unload the front and slacken the head angle.
C, clamp the knees on the tank HARD, and loosen up on the handlebars, the bike WANTS to go straight. In the aviation world, it's called PIO (Pilot Induced Oscillation). You are consciously or unconsciously trying to correct, and using too much input, which sets it off the other way.
That's exactly opposite a lot of the advice I am getting. I was told tank bags were good to put weight forward so the bike isn't "butt heavy". And as far as moving back, the overwhelming majority says shift body forward and lower while loosening grip and slowly easing of the throttle.
 

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Discussion Starter #10
Similarly loaded it happened to me also, not bad but enough to scare the s**t out of me. Something about the geometry / suspension I can't define. I simply slow down loaded like that.
Yeah, I slowed down to 60 and under on the curvy mountain roads and had no problems the rest of the 425 miles that weekend.
 

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I pretty much agree with most of the advice/opinion. UNFORTUNATELY "Tankslappers" often cause fatal high-end crashes. They are much more likely to occur with " dual sport" bikes than with touring bikes for a number of reasons, most of them have been noted. The best advice we need to follow, is learn to understand suspension,proper loading of bike and keeping the speed down.
 

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That being said about suspension and all does anybody here adjust their rear? Is there even a way to? I noticed the front feels sloppy and I'd like to raise it up some. Any input would be appreciated. 🍻


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Depending on your weight(>180lbs.) it is a real good idea to change your shock to something a bit more HD. Like a Progressive 465 or something similar .

M
 

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Thanks masterlink, but meanwhile is there any adjustment on the stock shock?


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Thanks masterlink, but meanwhile is there any adjustment on the stock shock?


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There are preload and dampening adjustments on the stock rear shock. You should see a bolt head on the left side of the shock in the middle with a kind of decal or stocker behind it with horizontal lines. That's the preload adjustment bolt. I believe adjustments range from 1 to 5. I run mine on 5. If you're interested in adjusting it, I would look for more information about what those lines mean. Apparently the bolt/adjustment mechanism is easily broken if you try to force things; i.e. not knowing exactly which line is the "5" line and perhaps trying to force it past that point. As I recall there are no reference numbers on that decal, just lines, so you have to be able to decipher them to know exactly what setting you're on, but I could be wrong. If you don't have an owner's manual, I could scan the procedure from mine and send it to you.
 

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I don't know..but I bet someone on here does. BTW If one ever experiences a head shake-tank slapper type issue,slowly apply FRONT brake to load the font end more. That is my understanding. IS THIS ACCURATE?? I would like to be certain.

Thanks.
 

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I noticed the front feels sloppy and I'd like to raise it up some. Any input would be appreciated. ��


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If you're not going for an aftermarket shock and are tall enough that they won't bother you, I would recommend a set of raising links for the rear suspension. They will not only serve to increase the effectiveness of the stock rear shock, but will also tend to make the bike more "nose heavy" by, obviously, raising the rear. They don't cost a lot and take maybe 10 minutes to install.

I don't sit around and analyze the geometry and suspension of my KLR, but I could tell an immediate difference when I went on a post-installation ride and it was a difference I really liked. Noticed I cut off your quote to where it doesn't make sense, but I'm sure you were talking about raising the rear.
 

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That being said about suspension and all does anybody here adjust their rear? Is there even a way to? I noticed the front feels sloppy and I'd like to raise it up some. Any input would be appreciated. ��


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Front feels sloppy? Check the head bearings. Do you have a fork brace? My front end used to feel like it was blowing around in the wind until I got a fork brace. Front end is solid now.






There are preload and dampening adjustments on the stock rear shock. You should see a bolt head on the left side of the shock in the middle with a kind of decal or stocker behind it with horizontal lines. That's the preload adjustment bolt. I believe adjustments range from 1 to 5. I run mine on 5. As I recall there are no reference numbers on that decal, just lines, so you have to be able to decipher them to know exactly what setting you're on, but I could be wrong
There are five positions for the Preload and they do have numbers. See Planalps post above.
 
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