Instability at highway speeds ! ?

I've felt my bike weave slightly while getting into an air pocket of a semi before, but again just the other day I hit a small pothole which put the bike into a small wobble (or weave... whatever you call it). It kind of concerned me, so I started experimenting with shaking the bars just a tad, and holy CRAP, this bike really goes into an almost tank slapper mode if you move the bars much. It's very unstable and kind of scary, I didn't want to push my luck and find the limit where it won't recover and where it puts me down.

What I wonder is if this applies to all of these WRRs or if it's because I have the lowering link on mine? The back end is about an inch lower than the front. I wonder if there is anything in my suspension setup (keeping the link in place) that I can adjust or tighten up to stabilize the bike?

If you didn't also slide your triple tree down your forks an equal amount to what you lowered your rear the geometry has changed sufficiently enough to cause problems.

So you purposefully induced a "high speed" wobble then wonder if that "instability" a natural thing for all R's??????????

I'm not seeing any logic here at all.

IndigoWolf wrote:

If you didn't also slide your triple tree down your forks an equal amount to what you lowered your rear the geometry has changed sufficiently enough to cause problems.

my wrX is lowered 1 inch in the rear too. front is unchanged. just wondering, what kinda effects does it actually do to the bike???

Check out YamaLink's site for info on lowering the front to match the rear:

http://www.motorcycleloweringlinks.com/index.php?content=yamaha-lowering-link-wr250xr

Sarah

Although I feel you might get your bike dialed-in to make it better, I highly doubt you'd ever make it feel like a heavier, more ponderous-feeling bike as far as straight line stability at highway speeds goes because, to me, this what it sounds like you are expecting.

My advice:
Keep your hands on the bars where they belong and quit with the experimentation in stability while on the highway.
I believe you could take a brand-new WR-250R off the showroom and it would behave like that.
Sounds normal.

I agree with YZect....I've gone as fast as I can on the highway with my bike stock and now with dunlop 606s and it feels unstable at high speeds,,a few weeks ago I was on the highway on a slight downhill and my speedo read 102,,,I know my speedo is waaaay off but it felt like I was doing 300mph,,,,I don't think this bike is for the highway,,,but I didn't buy it for that.........................Jason

by the way i've done what OP did many times on the hwy at 60mph+. i was curious so i just shook the bars and the bike went into a small wobble. but i think due to the steering geometry (bars higher than sportbike), once you stop shaking the bars your arms and upper body act as a natural steering damper, and everything goes to normal.

motokid wrote:

So you purposefully induced a "high speed" wobble then wonder if that "instability" a natural thing for all R's??????????

I'm not seeing any logic here at all.

It's real simple... hitting a pothole or even if you hit debris in the road will set it off, so it's kind of important to see just what we're dealing with before it becomes a problem at an unexpected time. I generally hate unexpected tank slappers.


I did raise the forks up as high as they would go.... and with that there is the 1" differential.

YZEtc wrote:

Although I feel you might get your bike dialed-in to make it better, I highly doubt you'd ever make it feel like a heavier, more ponderous-feeling bike as far as straight line stability at highway speeds goes because, to me, this what it sounds like you are expecting.

My advice:
Keep your hands on the bars where they belong and quit with the experimentation in stability while on the highway.
I believe you could take a brand-new WR-250R off the showroom and it would behave like that.
Sounds normal.

Yes! usually that is the best thing, both hands on the bars. ...but the other half of it is the bike is a bit unstable with only one hand on the bar. I was adjusting my camera bag over my shoulder and noticed a slight weave. I know it's not really meant to be a road bike, but just wondering if any of this is due to the suspension lowering (softening) in the rear, or if it's a characteristic of the bike in general. The link swap is easy enough, I may switch back and see if there is any difference..... I'm kind of doubting it though.

I feel my bike has this characteristic as well.
-606 tires
-factory lowering adjustment, forks too.
-now have all the clickers set as standard from the manual
*I even tried moving the forks back to stock height/ without the rear, as an experiment...no perceivable difference

I am comparing my bike to a 2010 stocker that's almost broken in, to the manual.
Its night and day difference how his bike tracks than mine, off road or on road.
At this point, its gotta be the tires...or I need to repair something.
Nothing appears to be broken , loose or anything like. Everything works smooth , without play.
My bike is rideable...just doesnt ride as nice as my buddies...and we both agree.
My experience in motorcycles is quite limited, so I guess I need the right pro to help from here.

mucker wrote:

I feel my bike has this characteristic as well.
-606 tires
-factory lowering adjustment, forks too.
-now have all the clickers set as standard from the manual
*I even tried moving the forks back to stock height/ without the rear, as an experiment...no perceivable difference

I am comparing my bike to a 2010 stocker that's almost broken in, to the manual.
Its night and day difference how his bike tracks than mine, off road or on road.
At this point, its gotta be the tires...or I need to repair something.
Nothing appears to be broken , loose or anything like. Everything works smooth , without play.
My bike is rideable...just doesnt ride as nice as my buddies...and we both agree.
My experience in motorcycles is quite limited, so I guess I need the right pro to help from here.

Thanks, thats good info. Maybe it is in the lowering link?? ... or the softening effect from the higher leverage on the shock.

My tires are the stock units with about 2K miles. I think I'm going to retorque all the fork and swingarm bolts to see if that will help. Too, I may stiffen the rear suspension up a bit. The front is much stiffer than the rear, that may be part of it.

zone47 wrote:

.I generally hate unexpected tank slappers.

Me too... ...but I'm thinking I would dislike the self-induced ones even more.

zone47 wrote:

I generally hate unexpected tank slappers.

I can see pissing around with it a little bit exploring where unstability starts - but I sure as hell wouldn't try nearly inducing them deliberately.

Quote :

I did raise the forks up as high as they would go.... and with that there is the 1" differential.

I have the Yamalink on my bike. It's fine - about what I expect a bike like this to behave like on the road. Hitting potholes or anything else on the road (not counting boulders and tree stumps) doesn't cause instability.

However, I did not raise the front forks all the way in attempts to keep up with how much the link lowered the back. I think the Yamalink folks say something about that. I can't remember what I raised my forks, but it wasn't as far as they could go.

Lots of lowering links out there with their owners having no complaints about the handling of the bike. You might look at lowering the forks first and other parts of the setup. If you do have a stability problem, it has to do with something other than the lowering link, in my opinion.

I've had the same thing happening to me. I was going about 75kmh on a gravel road when I hit a pothole. The tail started to weave, I slowed down to a stop, adrenaline pumping thru my veins. Wasn't a good feeling. I haven't lowered mine, mine is an X with a knobby DOT tire on the back and a 21" front wheel on the front. I thought the knobby rear tire was the reason for it.

Weird things happen with the contact patch on a tire that is worn, if you think of where the tire touches the road a worn tire can go from the center to quite far off center (and back and forth hence the headshake) in only a slight amount of lean angle where a new tire would be progressive, add to this the lowering link, maybe odd profile or width aftermarket tires, rear spring preload, different tire pressures etc etc and you can have something quite different from stock, and yes a flat spotted rear tire can be the cause
Having said that I do the same on my R (wiggle the bars) i do this kind of stuff on every bike just so I know what it will do
Mine has a tendency to shake the head too, I just replaced the tire with a Mefo of the same profile but have not ridden it yet
Steering head adjustment can help, if you have adjusted your bike to where you like and now have a headshake you can buy a steering damper

Have you set the sag? When I get a bit of wobble in the front, it's usually because I've added to much weight to the back. Once I set the preload the wobble goes away. Sometimes loose steering head bearings can add to the problem, also an out of balance front wheel.

Granted - I have an X and not an R - and my bike is not lowered at all, but:

I routinely let go of my bars when riding. Yes - both hands.

When coasting down to stop lights on open, deserted stretches of roads I'll let go of my bars completely.

At anywhere from 15 mph to almost 45 mph I can let go of my bars with total confidence and ease of mind.

My X feels so planted and stable up to about 80mph.

Over 80mph things start to get funky with the front end. I attribute that to the Distanzia front probably being off-balance a bit, and the wind buffeting on the front fender and handguards.

I can't imagine what knobbies would feel like at elevated speeds, but I would also assume that's part of the nature of the beast.
Knobbies are not designed nor intended for elevated highway speeds.

Also, what tire pressures you running?

Knobbies tend to be lower psi don't they?

Street tires are usually in the mid-twenties in terms of psi.

Don't you run knobbies down in the teens to low teens?

motokid wrote:

Granted - I have an X and not an R - and my bike is not lowered at all, but:

I routinely let go of my bars when riding. Yes - both hands.

When coasting down to stop lights on open, deserted stretches of roads I'll let go of my bars completely.

At anywhere from 15 mph to almost 45 mph I can let go of my bars with total confidence and ease of mind.

My X feels so planted and stable up to about 80mph.

Over 80mph things start to get funky with the front end. I attribute that to the Distanzia front probably being off-balance a bit, and the wind buffeting on the front fender and handguards.

I can't imagine what knobbies would feel like at elevated speeds, but I would also assume that's part of the nature of the beast.
Knobbies are not designed nor intended for elevated highway speeds.

Also, what tire pressures you running?

Knobbies tend to be lower psi don't they?

Street tires are usually in the mid-twenties in terms of psi.

Don't you run knobbies down in the teens to low teens?

When you take you hands off the bars as you are decelerating to a stop, and the bars start to shake, it's usually another sign that you rear shock preload is too soft.
I have an X with 4.60 x 17 knobby on the front with 8 lbs pressure and I don't have any problems up to 75 mph. I usually ride the canyon twisties to the dirt at 50-60 plus with out any problems. It's so much fun that it's hard to hold back.

Very often when I am riding this bike at high speed the thought comes into my head that this bike is so stable its unreal. This bike feels so planted and glued to the road. Don't know what the OP's problem is with his bike but it NOT normal.

Yeah, can't say mine's done that. The only thing that might be considered close was when i had too much air pressure in the front , it was a bit squirrely but certainly no shaking. Aired down, the bike stays where it's supposed to. I've got the Yamalink and lowered in more ways than one, nothing like you're experiencing tho.

I went about 90 miles on it today going over all kinds of roads, from freeway to choppy dirt roads and I didn't have any problems. Maybe the pothole incident was unique ... it still makes me a bit nervous .... that tank slapper feeling where you don't know if it will go out of control or pull out of it

Concerning the lowering link, I thought about it and don't think that's an issue. With the link, the bike is actually slightly raked out which should add to straight line stability. The softness in the rear and stiff front may be another story. Too, I may pump my tires back up a bit. I had them slightly softer for dirt, but maybe they are too soft for street.

I'm not going to worry too much about it. I can always add a steering damper if it bugs me enough.

Tire pressure is a big thing it seems. I know a lot of ppl run higher pressure on the tarmac, but with knobbies there isn't much contact patch when you are running like that. I know you do get better return on wear at higher pressure, but in relation to stability (at least in my view) I'd rather run a lower pressure, have more contact and stability. I can still air them down when I hit the dirt, but I don't really have to drop them a lot. I ran 21 up front and 18 on the back on my 606's and got over 8k on them...so I can't say that the wear was an issue. I'm running the same on the Pirelli's and it's a MUCH nicer ride.

I let go of my bars today at about 55 mph.

"Look ma - no hands!!!!!!!" (don't try this at home kids......)

Rock solid.

If I had cruise control I bet I could have gone for miles like that.

I bet you wouldnt do it with one hand on mine...lol...I'm jealous