I have had an 07 s4rs for about three months now and have put close to 5k miles on the bike. the bike is an absolute blast to ride around town as well as in the twisties. but as soon as the speed passes above 110 or so there is a very disconcerting wobble that does not go away, regardless of body position or acceleration/deceleration. I've played with the suspension and put a steering damper on the bike and the bike still seem to have it. the bike has never been down. does this sound normal to you guys?
You might want to find a local suspension Ghuru and start with sag and ride height. Also make sure the head bearings are properly adjusted.
This might seem crazy but have you considered slowing down?
On a serious note, does the wobble come from the front end? Or just in general?
the sag is set up for my weight and I raised the ride height about an inch from lowest.. how do I check the head bearings?
Quote from: arai_speed on August 12, 2008, 11:20:14 AM
This might seem crazy but have you considered slowing down?
On a serious note, does the wobble come from the front end? Or just in general?
haha.. never crossed my mind.. kidding. I very rarely reach those speeds but the fact that the bike behaves that way when I happen to does bother me. from what I can tell the wobble seems to be coming from the front but how do I tell for sure?
Stiffer front springs?
Different tires?
I also have a odd wobble at any speed above 70. Does it feel like the bottom half of the bike wants to shift side to side? Not to be confused with the steering wanting to turn side to side. I notice it most when I go over uneven pavement that runs close to parralel with the road. How exactly is your ride height diferent from stock? Is the front higher or lower, same ? for the back?
Quote from: MAXdB on August 12, 2008, 11:21:07 AM
the sag is set up for my weight and I raised the ride height about an inch from lowest.. how do I check the head bearings?
Have you checked to make sure all the little wheel weights for balance are still attached? I'm assuming you also meant 110 mph not kph...My s4rs is fairly stable in the high 90's mph, but by then and above the wind blast consumes lots of my attention. How resistive do you have your damper set?
+1 on Howie's suggestion of checking the head bearing...possibly damaged during wheelies
the wobble is just like overcaffeinated described.. side to side involving the entire bike. as far as ride height, I raised the rear using the ride height adjuster.. the front has not been changed.
I don't think the head bearings could have been damaged from anything I've done simply because the wobble was there since I bought the bike brand new.. but how would I check the bearings if I were to decide to check that?
The answer you should accept is "don't go that fast".
However, you might want to consider different tires. When I had a Bridgestone BT-010 on the front of both of the Monsters that I owned, there was a definite high speed wobble there from about 80 mph on up. Switching to a BT-020 made it completely disappear. One Monster had a steering damper and the other didn't, and that didn't seem to make the slightest difference.
I happen to like both Pirelli and Avon sport touring tires for good, stable high speed behavior.
But you really should keep the speed down on public roads, especially if you ever ride in California where you get double the points for speeds over 99 mph.
Quote from: ScottRNelson on August 12, 2008, 03:03:14 PM
The answer you should accept is "don't go that fast".
However, you might want to consider different tires. When I had a Bridgestone BT-010 on the front of both of the Monsters that I owned, there was a definite high speed wobble there from about 80 mph on up. Switching to a BT-020 made it completely disappear. One Monster had a steering damper and the other didn't, and that didn't seem to make the slightest difference.
I happen to like both Pirelli and Avon sport touring tires for good, stable high speed behavior.
But you really should keep the speed down on public roads, especially if you ever ride in California where you get double the points for speeds over 99 mph.
What tires and what tire pressure are you running? And how much do you weight?
I have the same bike as you and I have not experienced the wobbles you describe.
I weigh about 180 or so with my gear. right now I've got the stock pilot powers that came with the bike. I have used the pilot powers, both the regular and 2ct, for other bikes and have never experienced this type of behavior so I thought it had to do with something other than tires... but maybe this bike is just more sensitive to this type of stuff.
the pilot powers are set to 33 psi front and rear. the rear will probably need to be changed soon but is not squared off as most of the miles were done in twisties... and since the bike has done the wobbly thing since I took it off the dealeship floor, I don't believe it has to do with the tire being worn.
as far as my speeds, I will admit I do exceed the speed limit here and there but exceeding 100 is far from being something i do often. I am concerned because Im worried that this sort of characteristic may be hinting at some sort of underlying problem.. especially as I plan on taking the monster to the track soon.
btw, I appreciate everyones help! thanks guys
Try raising the rear tire pressure to 36. Probably won't help, but it won't hurt. Now that we know it is wobble also check the swing arm Make sure the bolts are tight and there is no play. Check for loose wheel bearings too. To check the head bearings you must suspend the front of the bike so the tire is off the ground and the bearings are not supporting weight, in other words, a front stand won't do the task. How you do it depends on what you have available. Same with the swing arm.
... 110 mph ... fast ... I trust your fully aware that if anything goes wrong your toast ... with no [bacon], that being said I do occcasionally push my M 800 03 to that speed on wide open highway when I know no one will be mearging on; what always amazes me was it is completely stable. thats with 22 k miles a new x ring chain; old front tire and newish rear "Z rated" Perellis, rear with a hole patch no less.
I'd guess to take the bike in and get the head bearings checked; ... front & rear wheel bearings; you can change the front steering angle by adjusting the forks up and down; mine are fully extended; and get the tires balanced and checked. Something is off; let us know what the problemo was when you pin her.
Cheers DD [moto]
You indicate that you've raised the rear suspension height with the adjuster. By doing that you've quickened the steering (decreased rake and trail) which will make it less stable.
Did the bike wobble before raising the rear suspension? It might be worthwhile to lower it back to stock and see what happens.
Quote from: ScottRNelson on August 12, 2008, 03:03:14 PM
The answer you should accept is "don't go that fast".
However, you might want to consider different tires. When I had a Bridgestone BT-010 on the front of both of the Monsters that I owned, there was a definite high speed wobble there from about 80 mph on up. Switching to a BT-020 made it completely disappear. One Monster had a steering damper and the other didn't, and that didn't seem to make the slightest difference.
I happen to like both Pirelli and Avon sport touring tires for good, stable high speed behavior.
But you really should keep the speed down on public roads, especially if you ever ride in California where you get double the points for speeds over 99 mph.
Per the above quote, I have an S4RS and from day one it was a "nervous" bike. Even after fulling dialing in the suspension, raising the rear, damper (for those Oh Shit moments) air pressures adjusted to a multitude of settings yadda yadda yadda. Not until I
replaced the Michelins did the bike stop being "nervous". I knew it was the tires after riding some rain grooves on the freeway and the make the beast with two backser felt like both tires went flat!! [puke] I won't go into all the reasons I hate Michelins.
FWIW, my bike transformed with the Pirelli Diablo Corsa III's and now I'm back on my favs, the Metzeler Sportec M3's (the best!! IMHO. Steel belts baby!). Also, and this just may be a personal pref but after going to a 6.0 BST in the rear which necessitated a change to a 190, the bike is absolutely rock solid now. Nothing but shear 100% unadulterated hooliganism upsets this thing now! God I love a 190/6.0in rear!! [clap]
Interesting thread. My S4RS WAS rock solid when I 1st bought it. I question why I even need ed a Damper !!!.
2 weeks ago I install one of my track take offs. A Metzeler. The guy who did it couldnt balance the tire cause he didnt have the spacers for a single sided rim.
Now the bike has a wiggle while accelerating from 100 to "Alot faster" mph.
The Pirelli I took off the back was squared. Even without a tread down the center it was solid. The Metz has a good center. I have a Pirelli on the front still.
I think my prob is tire combo,,,or tire balance. THat's likely the same problem that U R having. Probably tire balance !!!
Keep us posted when U find the fix.
Quote from: MAXdB on August 12, 2008, 11:21:07 AM
the sag is set up for my weight and I raised the ride height about an inch from lowest..
Quote from: speedevil on August 13, 2008, 05:23:38 AM
You indicate that you've raised the rear suspension height with the adjuster. By doing that you've quickened the steering (decreased rake and trail) which will make it less stable.
Did the bike wobble before raising the rear suspension? It might be worthwhile to lower it back to stock and see what happens.
+1 - Did it wobble before you raised the rear. 1" seems like a lot for a single adjustment?
Quote from: DarkStaR on August 13, 2008, 07:56:09 AM
+1 - Did it wobble before you raised the rear. 1" seems like a lot for a single adjustment?
I raised mine 3/4 inch and it was a great improvement but the bike was still "nervous" to me.
I seriously doubt if the wobble, as described, has anything to do with the rear ride height.
Its got to be wheel balance or an actual warped wheel or bearings.
Get the wheels balanced properly and check the bearings for any free play. Check the rims are true, ridden up any kerbs or landed heavily on the front?
Adjusting the suspension is may cause it to handle like crap, not wobble side to side.
At speed the bike can feel a little "light" and unstable on the front, but this is at 130+ mph.
If you are weaving at speed, then I suggest you relax your grip on the bars and try to tuck in behind the screen. Try to wear form fitting clothes/leathers that are not flapping in the wind.
As a start run the tyres at makers recomended pressures and make sure they have plenty of tread left. I have Pirelli Corsa IIs that suit the balance of street/circuit that i do.
I added 1 cm of ride height to the back (Measured from tip of rear mudguard) and it did improve stability. I am running standard springs and preload with a couple of clicks of additional damping front and rear. I am not that heavy.
And no don't slow down at all otherwise what is the point of an S4Rs?
Thanks to everyone for their input.. I've don't a couple things to see if I could relieve my bike of this wobble including checking the tire pressure, redo my suspension front and rear, as well as (try) to check my bearings..it does feel a little better with the tire pressure higher and suspension a bit softer. now when going straight, the bike seems to be alright but when I try to go through turns at high speeds, I still get a wobble..
also I was looking at my front tire and noticed that there were two sets of wheel weights on either side in different points of the wheel.. is that normal?
If the wheel was dynamically balanced yes. Also many techs split the weight. The only way to know is to remove the wheel and re balance. You said your rear tire is almost gone. If there is a wear pattern that is causing instability the only fix is a new tire.