What's with the wiggle?

[explorer72]

Ok, I've been riding for awhile but the other day while on my 'newer' ride (ZR-7S) I noticed something in the handling of the bike and just wanted to know what it is. I'm not too concerned as to a fix (I know it's just the way the bike is designed I'm sure) but just for my own knowledge I'd like to know.

So when you are going at high speeds (80 to 90+) in a slight curve what causes the bike to wiggle/flex back and forth? Is it just the frame flexing? Is it the front suspension causing that? I'm just at a loss on what to call that.   Please enlighten me.  

[Stray Cat]

It could be many different things. Tires, weight distribution, frame flex, fork flex, suspension settings, or a combination of several of these. I would start getting the static ride heights set, and go from there. How old are the tires? Have you messed with tire pressures at all? Does it go away with more lean?
Lots of things.....

[explorer72]

It could be many different things. Tires, weight distribution, frame flex, fork flex, suspension settings, or a combination of several of these. I would start getting the static ride heights set, and go from there. How old are the tires? Have you messed with tire pressures at all? Does it go away with more lean?
Lots of things.....

I notice more at higher speeds, under 80 even in tight turns I don't notice it at all. Now once I get to 90+ I really start to notice it. The tires are kinda new (new meaning they have about 5k on them), I usually run them at 36psi front and bike. I know my bike has a suck (soft) front suspension but at this point I wouldn't know a 'dialed in' front suspension over a stock one. This is my first 'Sportbike' (all my other rides being either cruisers or old school) so I'm still getting used to the handling quarks of the thing. My frame is tubular steel (not a boxed aluminum one like on most race bikes), so I also chalked it up to that being the issue. So how do you go about getting the static ride heights set?

[Thor]

Tires.  Buy new ones.  Your front is cupped.  Run your hand over the front tire and if you can feel ridges (you may not be able to see them), then that is the problem.

Yes, the stock suspension absolutely sucks on that bike, but it isn't too hard to remedy that.

[explorer72]

Tires.  Buy new ones.  Your front is cupped.  Run your hand over the front tire and if you can feel ridges (you may not be able to see them), then that is the problem.

Yes, the stock suspension absolutely sucks on that bike, but it isn't too hard to remedy that.

Perfect, will do   I think I might have even noticed some unevenness to the front. What causes that btw? I have a pair of Pirelli Diablo Strada on it right now, suppose to be a good tire for how I use the bike (I mostly use it for commuting).

Yeah I read about the suspension on that bike, I have the links to the progressive springs that should help that out.

[Stray Cat]

5k (if that is 5,000 miles) the tires are probably on their last legs. Start there and move on if that doesn't cure it.)

[explorer72]

5k (if that is 5,000 miles) the tires are probably on their last legs. Start there and move on if that doesn't cure it.)

Sounds like a plan, thanks for the input everyone  

[Zerosum]

I wonder if it has something to do with the tubular steel, internal frame.  I used to have a Yamaha XJ400 twin with a simlar frame, and I remember feeling a similar wiggle.

Every bike since then (Hawk, VFR, V-Strom) has had a perimeter aluminum frame, and I haven't felt the "wiggle" since.

[HipGnosis]

How many miles on the bike?
I'd check (or have checked) the steering head bearings and the swingarm bearings (though swingarm is a long shot).

[explorer72]

How many miles on the bike?
I'd check (or have checked) the steering head bearings and the swingarm bearings (though swingarm is a long shot).

The bike has 15k on it, I'm about to take it in for a completely service on it, I'll have them check that too. Thanks!  

[sammyseaman]

How many miles on the bike?
I'd check (or have checked) the steering head bearings and the swingarm bearings (though swingarm is a long shot).

 

[HipGnosis]

After thinking about this a bit (and re-reading the description) I suspect tire wear.
It sounds like you're transitioning from the flattened, center part of the rear tire to the outer tread. The transition is an 'unusual' phenomenom.

It's possible, but less likely, to happen with the front tire too. I had that happen on my trip to deals gap when my front tire was starting to scallop or cup.  There was a certain lean angle the tire simply didn't like. It made for an interesting trip - esp before I realized what was going on.

[brianm767]

My son had the same thing on his Blackbird, never experienced it on my two Blackbirds, but on his, a new set of Avon Storms fixed it, suspect cupped tire.

On all my bikes, XX's, busa and ST1300, cupped tire will cause wobble on deceleration at lower speeds if you let go of the bars, Dont try it! almost didn't get my hands back on the bars once on my Hayabusa, it was the worst.

[trentwebb]

This may be elementary, but you don't hear any clunking when coming to a stop do you?  Loose steering head bearings will cause a wiggle throughout the whole bike when giving steering inputs into turns.  

[Roaddog]

Some bikes are sensitive to tire selection to the point of not wanting to behave with anything other than factory-spec rubber, especially on the front. Also, running lower than recommended tire pressure can cause handling quirks with less-than-stellar suspension.

[Dunewar]

I also have a ZR-7s, and had the same thing. It is down to the soft front suspension and tire selection. I replaced the suspension with Hyperpro progressive springs (both front and rear), and put Bridgestone BT-21's on the bike. This has totally transformed the bike! If you ever consider one mod, the progressive springs are it!!!!! On the standard bike, the front and back suspension are not in balance.

It's not that expensive, I payed about 500€ for maintenance, suspension + installation and steel braided brake lines + installation.

Other than that, it is the perfect sport-touring bike for me. I feel right at home in the seat, and I have no problem keeping up with more powerfull bikes. Last saturday I even left a Blackbird behind in the curvy section of a tour in northern France.

[ibppjr]

If the tires are in decent shape, my 2 cents says soft rear suspension settings.  If the spring preload is adjustable, I'd crank some in and see if the wiggle goes away.  Best of all its free.

[MuddDawg]

Any uptate?

I ran Strada's on my Bandit 1200 and I got 10k out of them and never noticed this issue.  I put another set on right before I sold it.  If I could get 10k out of them on that torque monster you shouldn't have much of a problem.

[bikerfish1100]

5K on a set of Stradas on a bike of that performance level is not at all excesive- should be able to easily see another few thousand miles. Also, I've found the Stradas to be pretty impervious to cupping, and that on a bike with suspension that supposedly aggravates cupping (Telelever equiped R11S).

i'd suspect suspension issues, front and/or rear too soft.
google "setting suspension sag" to help get the preload properly adjusted, then work at dialing in rebound & compression damping (as possible).

[boomerang]

How many miles on the bike?
I'd check (or have checked) the steering head bearings and the swingarm bearings (though swingarm is a long shot).

That's what I'm thinking! Maybe swing arm bushings. I'm also thinking that the previous owner of the bike must have flogged the shit out of it.