Yesterday I went out on an aggressive ride in the mountains with a couple of really good riders. This is the first time I was really able to ride to the edge of my comfort levels and really improve my skill. Pushing the bike, I was able to really feel the suspension working under me.

Now here comes to my problem.  Sometime when really pushing around a turn, the front end would wobble quite bad when exiting.  This was exacerbated if i was to hit a dip mid turn.  I don't really have to much to compare to, so I don't know what is causing this. Is this something that just happens when riding hard or is it something i should be able to tune out?

I have upgraded the suspension with .85 sonic springs in front and 15w oil and a Katana eras shock with preload 2 and damping at 1.  The rear feels very solid and defiantly firmer than the front. Could the firmer back vs the softer front cause this?  I weigh about 165 without gear (I guessed 180 with gear) and that is what Sonic recommended to me.  I will try and see if increasing the front preload helps.


Also, anyone else use the Katana rear shock?  It seems almost too heavily damped (i dont really know how to tell).  I know this is a common setup, so I was wondering how everyone else faired in getting this tuned. 

There's only so much you can do on a front suspension that isn't really adjustable without pulling it back apart. My best recommendation would be to try to find some good reading on body positioning and cornering. You could also see if there is anyone you ride with that you really trust to look as your stance while you're turning to see if anything needs improved on. If you say this was your first time to really push the bike I'd be willing to say some of the instability could be from your body positioning. I've been riding for 10 years and I guaruntee that if someone who knew what they were doing got behind me, they could tell me all kinds of things I do wrong. I've never really looked into it but I'm sure if I did I could learn how to work with my bike a lot better than I do.

One other thing to consider is that the GS has extremely light handling. It's very easy to throw around, and with the upright bars there isn't a ton of weight over the front wheel, so it doesn't take as much to upset it. That's one of the benefits of clipons, because it gets your weight over the front wheel and makes it feel a lot more stable. Nothing wrong with upright handlebars, but one of the characteristics is that you're trading some stability for the easy handling.

So anyway, there could definitely be something you need to do to your rear shock to make the front feel better, but I wouldn't be the one to give you a good answer, but looking into some corning technique at the same time you research the suspension will definitely help!

Instead fixed rate, I have progressive springs with a higher preload than recomended and 15W oil, the springs make the front end stiffer than stock, I guess your springs do the same. I also have a Kat shock in the rear, but don't know for sure the setup. Other thing you could check is the bottles bridge, I read some people changed it for a stiffer one.

However I'd take a look at the tires too. Until a few months I had a 130/80 Metzeler Z2 rear tire, and a 110/70 Avon Viper front, both pretty worn out. Then switched to tube-type BT090, and the bike feels extremely stable. Hope this helps.

that's a tank slapper. whenever the front wheel is upset, esp. during a turn, the front end develops an oscillation.

that's why sport bikes have steering dampers.

http://en.wikipedia.org/wiki/Speed_wobble

Do a search for -twist of the wrist II pdf- on google. It has great info on cornering.       

Quote from: tt_four on November 15, 2010, 11:19:05 AM
There's only so much you can do on a front suspension that isn't really adjustable without pulling it back apart. My best recommendation would be to try to find some good reading on body positioning and cornering. You could also see if there is anyone you ride with that you really trust to look as your stance while you're turning to see if anything needs improved on. If you say this was your first time to really push the bike I'd be willing to say some of the instability could be from your body positioning. I've been riding for 10 years and I guaruntee that if someone who knew what they were doing got behind me, they could tell me all kinds of things I do wrong. I've never really looked into it but I'm sure if I did I could learn how to work with my bike a lot better than I do.

One other thing to consider is that the GS has extremely light handling. It's very easy to throw around, and with the upright bars there isn't a ton of weight over the front wheel, so it doesn't take as much to upset it. That's one of the benefits of clipons, because it gets your weight over the front wheel and makes it feel a lot more stable. Nothing wrong with upright handlebars, but one of the characteristics is that you're trading some stability for the easy handling.

So anyway, there could definitely be something you need to do to your rear shock to make the front feel better, but I wouldn't be the one to give you a good answer, but looking into some corning technique at the same time you research the suspension will definitely help!

I actually had clipons on for about two weeks, I took them off because i had to raise the forks about 2 inches to get them on.  I was worried about causing exactly this instability lol.  I may try them out again.

Quote from: reload on November 15, 2010, 02:24:45 PM
that's a tank slapper. whenever the front wheel is upset, esp. during a turn, the front end develops an oscillation.

that's why sport bikes have steering dampers.

http://en.wikipedia.org/wiki/Speed_wobble

Is it common for gs500s to need steering dampeners? I didn't think the steering geometry was that aggressive.

Quote from: redhawkdancing on November 15, 2010, 02:48:16 PM
Do a search for -twist of the wrist II pdf- on google. It has great info on cornering.       

Readin it now, good book! thanks

Quote from: ameen on November 15, 2010, 05:45:40 PM
Is it common for gs500s to need steering dampeners? I didn't think the steering geometry was that aggressive.

In my opinion, every bike should have one. You can find one off a bike like mine for about $20 if you look around enough. It serves the same purpose, stabilizing the front suspension and preventing sudden, jerky movements. Speaking of which, I need to rebuild mine . . .

I've never had a steering damper and I'm still alive. I wouldn't mind one though for piece of mind. I've only had 1 tank slapper in 10 years of riding, but I guess that's what happens when you set your front wheel down when you're going 120mph  That problem was easy enough to fix without a damper, haha.

If you can piece one together for cheap go for it, but of all the mods people around here seem to love, I don't know if I've ever really seen anyone put a damper on a GS500.

As far as the clipons, I had mine under the top triple so I didn't have to modify the geometry, but it was a pretty step angle for me to lean all the time. If you take off the top triple plate that holds the handlebars, you're left with the main top triple that holds the front end together. Then you would only have to lift the fork tubes half an inch or so to get some clip ons on there, and you would barely have to mess with the geometry.

Quote from: tt_four on November 15, 2010, 06:42:47 PM
I've never had a steering damper and I'm still alive. I wouldn't mind one though for piece of mind. I've only had 1 tank slapper in 10 years of riding, but I guess that's what happens when you set your front wheel down when you're going 120mph

I've had a couple from accidental power wheelies, but it always works right out. I remember doing wheelies on the gs, sometimes it would do it a little if the angle of the front wheel wasn't dead on.

Quote from: ameen on November 15, 2010, 05:45:40 PM

I actually had clipons on for about two weeks, I took them off because i had to raise the forks about 2 inches to get them on.  I was worried about causing exactly this instability lol.  I may try them out again.


Is it common for gs500s to need steering dampeners? I didn't think the steering geometry was that aggressive.


Readin it now, good book! thanks

so ya had the forks hiked up during the trip? that definitely sounds like it could have helped create the steering wobble.

as you raise the forks up you're making the rake angle steeper. the gs is doing about 25 degrees stock. you could have been near super sport bike territory which is getting quite unstable.

a cbr600rr has a rake of 23.5 and has a steering damper for good reason.

i haven't seen a gs with a damper. just be careful with the suspension geometry

No, on this trip i had superbike bars and the stock geometry

  hmmm then just  the pos...lol jk

Doesn't the Kat shock raise the rear end?  If you raise the rear an inch you will reduce the rake about one degree.  What size and kind of tires?  A 140/80 rear for example will raise the rear about 3/4" and a 150/70 will raise it about 1/2" also further reducing the rake. 

when i first got my gs i was told the front springs were soft and to replace them with progressive springs.

now that ive done some riding on the bike and talked to a lot of other riders and pro's, ive learned to ride and not slam the front wheel. also progressive springs are no good for aggressive riding through mountains they are more designed for commuting.

The Progressive front springs are one size fits all and I think they are better suited to the heavier riders and a bit too stiff for the lighter ones.  The fixed rate springs are better suited for the lighter riders.  I put the Progressives on for my 02 trips to the mountains along with the Z4/Z2 radials and it was so much better than a 01 trip to the Smokies and Dragon done on a Dunlop touring rear tire and oem front springs.  I transfered the Progressive springs to the 02 GS in 03 after the 97 was totaled so they have over 100k miles on them now and are just about broken in nicely.     I was about 240# when I got the Progressives.  I have never had a hint of instability from the front end of my GSs but did have a steering wobble problem on a Nighthawk 650 I had before that and it was related to worn and cupped front tires and bad steering head bearings.  New front tire improved it and new steering head bearings eliminated it.

Quote from: reload on November 15, 2010, 08:20:00 PM

a cbr600rr has a rake of 23.5 and has a steering damper for good reason.

I remember it was a complaint when the 600rr first came out in 03 because they didn't have a damper on them. I guess they were just trying to save a couple dollars?

How bad shake you were getting on your bike? Were the bars shaking around a little bit, or was your front end yanking itself back and forth to the point that you thought you were going to die? There's a certain amount of movement in a front end that you'll get used to as you ride more aggressive more often. If you've ever watched video of the Isle of Man races, you'll see their front ends shaking all over the place and they just keep on moving. Obviously you're not gonna be riding as hard as those guys, but those are nice bikes most of which have dampers on them. To really be a 'tank slapper' the front end is just this forceful back and forth motion that pretty much just makes you start preparing yourself for death, haha. When I had mine I had absolutely no hope of getting out of it without crashing. Somehow it just stopped, then started again a second later, and then stopped again. I couldn't believe it, but I've been more careful since!

I bet after a few more aggressive rides you'll get more comfortable with it, loosen up your grip on the bars a little, and not notice the problem as much. If you do, then by all means go grab a damper on ebay and see if you can make it fit. Make sure you take some pictures for everyone here too! Once one person does it, you'll see dampers popping up on GSs all over the place.

What a tankslapper looks like to any one but the person soiling their pants:
http://www.flyingsnail.com/Sprung/tankslapper.html

Quote from: XLAR8 on November 16, 2010, 01:43:03 AM
when i first got my gs i was told the front springs were soft and to replace them with progressive springs.

now that ive done some riding on the bike and talked to a lot of other riders and pro's, ive learned to ride and not slam the front wheel. also progressive springs are no good for aggressive riding through mountains they are more designed for commuting.

I'm about 180lbs. Never had an issue with the front springs. Unless I'm practicing emergency stops, I don't notice them much at all.  Adjusted the rear shock a bit, and it was fine. I figured I would notice what everyone was talking about one day.   

Quote from: gsJack on November 15, 2010, 10:03:24 PM
Doesn't the Kat shock raise the rear end?  If you raise the rear an inch you will reduce the rake about one degree.  What size and kind of tires?  A 140/80 rear for example will raise the rear about 3/4" and a 150/70 will raise it about 1/2" also further reducing the rake.  

I am running stock size Sport demons.  The Katana shock does raise the rear end slightly, but what i am more concerned about is the different spring rate/dampening of the front vs the rear.  I don't know if that is a big deal or not, but the back definitely feels firmer than the front.

Quote from: Paulcet on November 16, 2010, 07:55:03 AM
What a tankslapper looks like to any one but the person soiling their pants:
http://www.flyingsnail.com/Sprung/tankslapper.html

It wasn't as bad as in that video, it was more of a front end wobble but i was able to ride out of it without it getting worse.  After the first time, i actually tried pushing the bike a little harder to try and see if i could figure out what was causing it and how to control it. Never really thought about getting thrown off lol.  
I wasn't able to get it consistent enough to figure it out.


On another note, as far as riding technique.  Should my weight be on the inside or the outside peg (or both)?  

If it didn't make you almost pee your pants, it probably wasn't a tank slapper, haha. Definitely explore it, just be careful to take your time. After riding a bike with clipons, the front end on the GS always feels unstable to me. My favorite thing to do when I'm riding in a straight line going 50mph+ is to gently wobble the handlebars back and forth. The whole bike starts shaking, haha. My XB does it too, but not as bad. Not really much you can do to stop that aside from getting used to the handling and know what will and won't make it wobble.

As far as your weight, I think most of it is supposed to be on your outside knee holding the tank. There isn't supposed to be any weight on your bars. You can't really put any weight on your outside foot since you're leaning the opposite direction, so any weight through your feet would be on the inside peg, but not a ton. That's definitely the kind of stuff that would be covered in the PDF someone linked to above, and his advice is definitely better than ours so try reading through there.