Head Shake Causes... Headshake

I searched and could only find one other post that covered potential reasons for head shake. So the condition I'm dealing with is...

I currently Have 90% Off-Road Tires on my WRR. When I take it on the Highway (70mph), I'm experiencing a really shaky front fork that feels like it could turn into a full-on tank slapper. What are the conditions that may cause Head Shake?

Is it the weight distribution front to back?
Tire Pressure?
Tire Type (Knobbies on the Highway)?
Other Reason?

This problem actually got me thinking and I ordered a GPR Stabilizer, but it hasn't arrived yet. I dont even know if it'll fix the problem. Really, I just wanted one!

whitea42 wrote:

I currently Have 90% Off-Road Tires on my WRR.


When I take it on the Highway (70mph)

Might be your problem right there.

Are your wheels and tires balanced?

What tire psi you running?

I have a 100% dirt front knobby on mine with a D606 rear. No steering damper.
Mine will, at times, start to wag it's head a little above 65mph or so but it has never gotten out of hand. I've had it up over 85 (GPS confirmed) and it has never gotten any worse than just a little "nervous". I don't worry about it. In fact it's kind of fun to move up and back on the seat and see how it effects the front end. A great excuse to get a damper though. I'd have one if I had room on my bars for it.

Scott P.

What tires are you running? I ran aggressive knobs on mine and the only set I ever had any nasty shake was with the Pirelli Scorpion Pro's. Wasn't really a head shake, more like just a real bad vibration.

I'm running Mitas M16 & M17 StoneEaters (Med-Hard Tires) at approx 24psi (prob a little less bc it's gotten colder here in Minnesota). I'll double check my pressure and confirm.
Check out Mitas M16 & M17 Thread (pictures of my Mitas rubber).

So the shake has never gotten out of hand, and I never tried moving forward/backward on the seat to see how it affects the ride.
I think i was probably leaning forward as I'm without a windshield and it's been below freezing a couple mornings on my way to work.

Did you consider if the possibility of the wheel being out of true? I don't know how often this happens on a motorcycle but it happens on my bicycles all of the time.

I ran those same tires and never had an ounce of trouble with shake. Got it up there in speed too, and they were really good that way, considering how meaty a tire they are.

I ran 90/10's (Scorpion Pros also) and had serious vibration at 70mph. Switched FRONT tire only and problem went away.

I'm very curious to know if a stabilizer will work for you with same tires. Please keep us posted.

So I checked my Tire Pressure last night when I got home and I think I might have found the problem...

Front: 4 Psi
Rear: 16 Psi

And NO, I'm not running a Tubliss system. Does anyone run Nitrogen in their tubes? I'm thinking i might have slightly pinched my front tube when I put the tire on. Those HD Tubes are a pain. Anyways, an update on the GPR Damper, estimated arrival via UPS is Friday, 11/11/2011.

I have UHD tubes from Michelin and the street legal knobbies (AC10) from Michelin. Best tires ever, no shake at any speed, incredible grip even on a wet road.
I don't know how they did it.

I would definitely check the true of the spokes, though.

I get some slight speed wobble on my X at 70mph or over, probably as I have a screen and big hand guards, high bars etc. Didn't do it before all that lot.

I need to take my front wheel off to fix the tube anyways, so I'm thinking I'll just take it into the shop and have the guys check both wheels and balanace them as needed. Maybe fill with Nitrogen if they've got it.

whitea42 wrote:

I need to take my front wheel off to fix the tube anyways, so I'm thinking I'll just take it into the shop and have the guys check both wheels and balanace them as needed. Maybe fill with Nitrogen if they've got it.

Check that the core is seating properly first. I once had an expensive tube that I thought was junk and it turned out that swapping a core from another tube made it work fine. Usually the cores not even bad, it just won't seat on that particular tube, but works fine on other tubes. Just a thought...

About headshake. When I first got my WRR, it would headshake terribly at speeds above 60. I had it on the highway a few days ago and I was doing 84mph and it was fine - obviously unhappy, but not a white knuckle ride. Keep in mind the rear is at full height and I'm using D606 tires. The only thing I had to do was sit a lot further back and move the rear wheel a bit further back (dropped a tooth on the rear sprocket).

This is what I recommend (in order of difficulty):

• Do not ride with your nuts on the tank. Sit so that your calves are almost vertical.
  
• Hold the bars loosely and grip the bike with your knees.
  
• If you have a large windshield or fender pack, take it off and see if it's the problem.
  
• Make sure your tire pressures are right. (too high can also make it wobble at speed)
  
• Adjust your suspension settings back to stock
  
• Try adding a little bit more sag in the rear suspension
  
• Lower the rear a little and make sure your forks were not moved up in the trees by the dealer or DPO. (They should be almost level with the trees with the fork covers above the trees)
  
• Drop some teeth on your front or rear sprocket (1 or 2 total) to get some chain slack - this will allow you to move the wheel back further. This only applies if your adjustment is currently almost against the stop.
  
• Add a steering damper
  

"•Do not ride with your nuts on the tank"

Man, ain't that the truth. After that much buzzing head shake would be the least of my worries. I wonder if SheWolf feels the same way or, well, lets just leave it at that, shall we?

"Try adding a little bit more sag in the rear "

That happens anyways once you get to be my age.

So I bought the bike a couple months ago and have not adjusted the suspension yet. The triple trees are flush with the fork tops. I haven't checked where the rear is set at because it felt like a good ride height for me when I bought it. Is there a special tool to adjust the rear shock? Tire pressure is up now at 20psi f&r. Thanks for the valve seat comment, and now that you mention it, I think I swapped the valve on my front tube when I installed them. Other then that, I'm running a 13/46 sprocket combo, and my wheel is nearly all the way back on the swingarm.

But Here is where I'm turned around. On a long stretch of road, err "Highway", I got the bike up to 80mph yamaha speed and started to play with my seat positioning, leaning fwd or back, etc. When I would sit up and move back on the seat, the wobble is back, but leaning fwd and moving up made for a stabile ride. Which tells me she's light on her forks. Now what?

***EDIT***

I'm wondering if my saddlebags on my wolfman rack add too much weight to the ass end of the bike. I usually keep my bike lock, some gloves, tire gauge, etc. in there. But all-in-all lightweight stuff. I'm about 185lbs if that's any help... And here's Pictures

whitea42 wrote:

So I bought the bike a couple months ago and have not adjusted the suspension yet. The triple trees are flush with the fork tops. I haven't checked where the rear is set at because it felt like a good ride height for me when I bought it. Is there a special tool to adjust the rear shock? Tire pressure is up now at 20psi f&r. Thanks for the valve seat comment, and now that you mention it, I think I swapped the valve on my front tube when I installed them. Other then that, I'm running a 13/46 sprocket combo, and my wheel is nearly all the way back on the swingarm.

But Here is where I'm turned around. On a long stretch of road, err "Highway", I got the bike up to 80mph yamaha speed and started to play with my seat positioning, leaning fwd or back, etc. When I would sit up and move back on the seat, the wobble is back, but leaning fwd and moving up made for a stabile ride. Which tells me she's light on her forks. Now what?

***EDIT***

I'm wondering if my saddlebags on my wolfman rack add too much weight to the ass end of the bike. I usually keep my bike lock, some gloves, tire gauge, etc. in there. But all-in-all lightweight stuff. I'm about 185lbs if that's any help...

IMO, there be your problem matey. I too am 185lb, and had to screw in a few turns of preload on the rear to prevent the rear from sagging too much, which causes the front to get light and shake. I betcha if you properly adjust your suspension, your shakes will go away.

-SM

If you think the front is too light you could try messing with the suspension - all the stock settings are listed in the manual so there's little chance of you making it worse. Tires pressures f/r should be different (19/26?) can't remember, but it's listed on your swingarm. Go for the upper rating because you + gear is probably above the lower rating. 80mph is still great for a dirtbike which was never really intended to perform well at those speeds.

Every riders idea of acceptable handing is different so what works for me won't necessarily work for you Keep us posted on what works and if you find a solution.

My shake.....

I tend to ride quite far back on my X, my legs are all of my 6ft 3 height.

So I sat forward, and shake has gone away, can pull 80 with ease.

Im sure my shake is down the the screen, big hand guards etc as stated before, but I'm glad I have found a work round :)

Steering damper is in but haven't given it a full test yet. But ordered some street rubber Shinko 705 tires today. Gonna save thee knobbies for the trail.

Now after i pulled the headlight forward, I'm having electrical issues. No turn signals or headlight.

Anyways, does anyone know where to get the tool to tighten the steering head nut?

whitea42 wrote:

Steering damper is in but haven't given it a full test yet. But ordered some street rubber Shinko 705 tires today. Gonna save thee knobbies for the trail.

Overkill.

Overkill? Or passion for the WRR?

whitea42 wrote:

Overkill? Or passion for the WRR?

Only overkill if you're trying to limit head shake.

I'm pretty sure the head shake was fixed when I actually put some air pressure in the front tire. The rest are just farkles because it's close enough to the holiday season that the wife doesn't check the credit card statements.

I'm running D606's with no head shake. I added a small fairing mounted windscreen and got scary shake right at 70 mph. Removed the windscreen and the shake went away. Put it back on and the shake came back. Hasn't been on since and no shake!

Took the bike out for some quality hooligan riding this weekend and No-Headshake! I'm pretty sure it was the 4psi front tire pressure that was causing issues, but I can't be sure. Thanks to everyone who contributed to solving my problem! I owe ya one....