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 Head shake

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Jeff d




PostSubject: Head shake   Thu Sep 17, 2015 4:33 pm

I've had a 2009 WR250R for about a month now.  It's got pretty bad head shake if anything upsets it above 65 MPH.  I started by searching and going through some of the recommendations.

-Tire pressure is good per the label on the swing arm
-It had a Yamalink lowering link that I removed as I'm 6' 2" and don't need any lowering.  Also extended the shock back to approximately the factory length bringing the seat height to the factory spec 36.5".
-Forks are in the fully extended factory position (They weren't before)
-Race sag was way off but I've adjusted it for my 200 lb self to 3.5" (Right in the middle of the 3-4" range)

All of the above pretty much made no difference at all.  I thought for sure it would be gone but it's not.  If I hit a bump, get a cross wind or shift too hard above 65 it starts and I have to back off the throttle to below 65 for it to go away.

The only two things left are to check rear wheel alignment more carefully (It's right according to the tick marks) and try different tires.  I currently have brand new Dunlop D606 knobbies on there.  I also have a set of some sort of more street oriented dual sport tires I can try.

I could also balance the tires but this really doesn't feel like what I've experienced in a 4 wheeled vehicle with out of balance tires.  It's more of a wiggle than a vibration.  I do have a bunch of Dynabeads I could throw in there but I was planning to slime the tubes for trail use.

Any other ideas?  I really don't want to have to spend $500+ on a steering stabilizer.
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Fiftygrit

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PostSubject: Re: Head shake   Thu Sep 17, 2015 6:19 pm

Did you check the bearings and tightness in the steering crowns, put the bike in the air and check for play, and how loose the steering is.
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wwguy

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PostSubject: Re: Head shake   Thu Sep 17, 2015 6:29 pm

At 6' 3" and 210 lbs. I had a similar experience when I first started riding my mine.  After doing most of what you've already done I found some additional relief with combinations of riding farther forward on the seat, carrying less gear on the tail, and carrying my 6 lb. bag of tools and tire repair gear in a Wolfman Enduro Carry-All bag on the front number plate over the headlight.

This is my first small dual sport bike, so I'm no expert, but I chalked it up to being the price to pay for riding a 300 lb. bike with dirt bike geometry on the pavement at highway speeds.

I eventually geared down to 13/51 and added a Scott's stabilizer for off-road reasons, so this problem is pretty much just a memory for me.  But it's a very real and uncomfortable memory.  I'm surprised there's not more frequent discussion about this.
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Jeff d




PostSubject: Re: Head shake   Thu Sep 17, 2015 7:04 pm

Yes, all bearings are good. Also, I've already tried moving forward and back on the seat and it had zero effect for whatever reason.

I'll put in the dynabeads and see if that does me any good. I have access to a tire balancer machine for car tires but I'm not sure if that can be used for motorcycle wheels or not.
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Fiftygrit

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PostSubject: Re: Head shake   Thu Sep 17, 2015 8:52 pm

Ya i have never seen a car tire balancer that could do bike tires, google balancers for bike tires you can actually make you own,
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66T

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PostSubject: Re: Head shake   Fri Sep 18, 2015 12:28 am

I'm 6.0 and about 110kg, but I've had no headshake ever worth noting. As above, I think it's worth balancing the wheels. I always do this, but I'm not fussy. My bike has rimlocks fitted.

All I do is get the stick-on strips of balance weights, push the axle through and support both ends on anything that's high enough. Note where the wheel settles after a couple of gentle spins, and weight up across the rim (ie through the spokes). Tap the lead with a light hammer so it conforms to the rim contour. Keep spinning and add weight opposite the low point until the wheel stops anywhere. It looks like shit but works really well, and weights don't seem to throw if I do it this way.

It only takes few minutes and makes a hell of a positive difference to your ride.  Apologies if you don't need this advice Shog
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dmmcd

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PostSubject: Re: Head shake   Fri Sep 18, 2015 6:53 am

I have this same issue, but at about 75 mph. I have a X, so I am running street tires. It goes away if I let off the throttle and stay below 75. Also I find if I put more weight on the front end it helps. My wheels are balanced.

It has a lot to do with the geometry of the front end, and I think the lightweight bike. Any small disturbance is enough to start a harmonic oscillation in the front end at high speeds. A damper would definitely help, but I spend so little time at 75 mph, that I just ride it out and forget about it.
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Jeff d




PostSubject: Re: Head shake   Fri Sep 18, 2015 7:04 am

Could I not just balance the tires by removing the brake calipers or pads and chain (To eliminate drag) with the whole bike on a stand?  Then just add weights in the normal manner to whatever point consistently stops in the up position.  Seems like that would be easier than removing the wheels and putting them on a balancing stand.

I used to be sold on the balancing bead thing.  I had used Dynabeads on motorcycles before without issue but who actually knows how far out of balance they were to begin with?  I had a balance issue with an old Ford ranger that I had so I decided to throw in airsoft BBs.  That actually worked great and eliminated my issues on that vehicle.  I then had balance issues on our mini van.  Shops had a very tough time getting them balanced so I bought like $60 worth of Dynabeads, threw them in there and it did nothing at all.  Had to bring them to a shop with a Hunter Road Force balancer, have the tires unmounted/remounted to remove the beads and they finally got them balanced correctly.  I saved all those beads but I'm hesitant to put them in.  I guess I could just replace the tube in this case though if I wanted them out.
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dhally

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PostSubject: Re: Head shake   Fri Sep 18, 2015 10:53 am

I had this problem on a previous bike, but not the WRR. My old KTM 640 used to do some head shaking. I removed the large solid panniers, and re-valved and re-sprung the suspension. I also balanced the wheels. No more issues.

On my WRR, I have ridden with fairly large loads on the rear rack and never had the issue. I do have spoke weights to counterbalance my rim locks. Stock suspension.

My only thought is maybe your front suspension needs rebuilt?
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dmmcd

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PostSubject: Re: Head shake   Fri Sep 18, 2015 11:59 am

Jeff d wrote:
Could I not just balance the tires by removing the brake calipers or pads and chain (To eliminate drag) with the whole bike on a stand?  Then just add weights in the normal manner to whatever point consistently stops in the up position.  Seems like that would be easier than removing the wheels and putting them on a balancing stand.

This is exactly how I balance my wheels. It is accurate to less than 1/2 of a stick-on wheel weight.

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Jeff d




PostSubject: Re: Head shake   Sat Sep 19, 2015 10:52 am

Well, either it wasn't balance related or Dynabeads don't work. I added the prescribed amount this morning and the wobble is still there. I'll go through a few more things before I go to the trouble of swapping tubes and balancing the conventional way.

I measured the distance from the swing arm pivot pin and the rear axle and one side is about 1/8" further back even though they're on the same tick mark. I'll have to come up with a more precise way to measure and get that straight.
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Jeff d




PostSubject: Re: Head shake   Sun Sep 20, 2015 2:48 pm

The rear was out of alignment by about 3/32".  Fixed that but still wobbling.

I guess tires are next.  I'll swap in the Kenda street tires one at a time, re-balance and see what happens.   The d606 rear is a 130/90-18 so I'm not sure if that could mess up the attitude, causing the wobble. It's significantly larger than the stock sized Kenda.
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dmmcd

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PostSubject: Re: Head shake   Mon Sep 21, 2015 6:43 am

I think it could be tire related, and also road surface related. My last set of tires were Bridgestone B016, which don't have a center groove. My current tires are Shinko Podiums and they do have a center groove around the front tire, and I never had a problem with the Bridgestones, but do notice a lot of front end weave with the Shinko. Could also be pressure related.
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morgan9283




PostSubject: Re: Head shake   Mon Sep 21, 2015 10:26 am

Jeff d wrote:
I've had a 2009 WR250R for about a month now.  It's got pretty bad head shake if anything upsets it above 65 MPH.  I started by searching and going through some of the recommendations.

-Tire pressure is good per the label on the swing arm
-It had a Yamalink lowering link that I removed as I'm 6' 2" and don't need any lowering.  Also extended the shock back to approximately the factory length bringing the seat height to the factory spec 36.5".
-Forks are in the fully extended factory position (They weren't before)
-Race sag was way off but I've adjusted it for my 200 lb self to 3.5" (Right in the middle of the 3-4" range)

All of the above pretty much made no difference at all.  I thought for sure it would be gone but it's not.  If I hit a bump, get a cross wind or shift too hard above 65 it starts and I have to back off the throttle to below 65 for it to go away.

The only two things left are to check rear wheel alignment more carefully (It's right according to the tick marks) and try different tires.  I currently have brand new Dunlop D606 knobbies on there.  I also have a set of some sort of more street oriented dual sport tires I can try.

I could also balance the tires but this really doesn't feel like what I've experienced in a 4 wheeled vehicle with out of balance tires.  It's more of a wiggle than a vibration.  I do have a bunch of Dynabeads I could throw in there but I was planning to slime the tubes for trail use.

Any other ideas?  I really don't want to have to spend $500+ on a steering stabilizer.

When I run my WRRs at 18 psi front and 10 rear I consistently get a wobble at 70+ mph.  You said your pressures were right but you may want to double check.

Years ago I had a terrible wobble over 55mph in a non-WRR street bike (MZ Skorpion fwiw).  After trying all sorts of things I finally replaced the rear tire as I'd just installed installed it and the problem went away. Definitely try your other tires.

I ride a lot on dirt but do ride to/from (~30 miles) on the street, some of it at high speed and I've never balanced a wheel.  I usually use 90/10 dirt/street tires.  I change my own tires in my garage and use UHD tubes so the wheels are almost certainly out of balance.  I never see wobble at 70+ (except when I run 18/10 pressures).

For this problem on the WRR a steering stabilizer will just mask the problem. I'd discourage you from installing a steering stabilizer until you sort this problem. I'll go a step further say say unless you're a pro pushing the bike hard or doing something unusual with your WRR a steering stabilizer is unnecessary.

for what it's worth I'm 5'10", 160lbs and lowered the rear the max available on the stock shock and the front about half that. The vast majority of my riding has been at that setting though I rode the bike a bit at the stock ride height and don't remember a problem.

Check wheel, swingarm and head bearings if you haven't. I don't remember for sure but there are I believe also bearings in the shock linkage--make sure those are greased and free moving. If the bike is low mileage and hasn't sat outside chances are the head and swingarm bearings are fine. My bike goes though wheel bearings reasonably often though it sees a fair amount of water. The WRR's swingarm is very easy to remove (to check the bearings).

Have you checked your spokes? After a friend's WRR wheel failed I check mine and several spokes were alarmingly loose. I'm not sure of the interval but it's a good idea to check that the tension is correct. I bought a ~$100 spoke torque wrench but there are credible methods of torquing with just a spoke wrench.

Have you checked the front sag? I mention it as the only way to adjust that (as far as I know) is to replace springs. If the PO adjusted the rear he/she might have replaced springs in the front and so could be way off for your weight and causing the wobble.

good luck, let us know what you find. The source of wobble is often interesting.

-morgan
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Jeff d




PostSubject: Re: Head shake   Mon Sep 21, 2015 10:51 am

Tire pressure is definitely good per the label on the swing arm. Added a bit, checked, rode it immediately up to 65 and the wobble was still there. I'd hate for it to be the D606 tires as they seem to work well off-road, are new, look cool and apparently were almost $100 a tire.

All of the bearings I've dealt with when it was on a stand feel solid. It only had 2,900 street miles on it when I bought it and was like new, stored indoors. I'd be surprised if anything is worn out already. I've since added 250ish off road miles and another 50 or so street miles.

I haven't checked spoke torque or wheel trueness. I will need to add that to my list.
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morgan9283




PostSubject: Re: Head shake   Mon Sep 21, 2015 11:10 am

Jeff d wrote:
Tire pressure is definitely good per the label on the swing arm.  Added a bit, checked, rode it immediately up to 65 and the wobble was still there.  I'd hate for it to be the D606 tires as they seem to work well off-road, are new, look cool and apparently were almost $100 a tire.

To be clear it's not a bad tire model but rather a defective individual tire. D606s work well on WRRs, it's possible you just have a defective individual tire. In theory that would be a warranty claim and Dunlop would replace the tire.

My buddy's front failed around 3k. Though they were a rough 3K: The bike was well worn, it had seen a lot of dirt prior to his ownership. Someone may correct me but to my knowledge truing motorcycle wheels is only a thing when they build the wheels. I'd focus on making sure the spokes are the correct torque.

-morgan
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wwguy

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PostSubject: Re: Head shake   Mon Sep 21, 2015 3:14 pm

morgan9283 wrote:

For this problem on the WRR a steering stabilizer will just mask the problem.  I'd discourage you from installing a steering stabilizer until you sort this problem.  I'll go a step further say say unless you're a pro pushing the bike hard or doing something unusual with your WRR a steering stabilizer is unnecessary.

I get the part about not masking the problem before you fix it, but disagree with your opinion that a stabilizer is "unnecessary" unless you specifically know how and/or where he rides.  I'm an intermediate rider and adding a Scott's stabilizer to my WRR has been a game-changer for me.  I can now ride tight steep rocky root-infested single track that I couldn't ride before on this bike.

It's not about "pushing the bike hard" or doing things "unusual".  I'm just a regular 50 year old guy who wants to enjoy riding my dirt bike where the other dirt bikers are riding.  A steering stabilizer makes a measurable difference to that end, especially considering the extra weight of the WRR compared to WRF etc.  Sometimes the difference in deflection absorbed by the stabilizer is the difference that keeps the bike on the trail and the mountain.

I rode this trail last weekend and had a blast, thanks in part to my stabilizer.  Better riders can probably ride it fine without a stabilizer, but for me it was "necessary". (This video is from someone else's ride on the same trail.)

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morgan9283




PostSubject: Re: Head shake   Tue Sep 22, 2015 9:26 am

wwguy wrote:
morgan9283 wrote:

For this problem on the WRR a steering stabilizer will just mask the problem.  I'd discourage you from installing a steering stabilizer until you sort this problem.  I'll go a step further say say unless you're a pro pushing the bike hard or doing something unusual with your WRR a steering stabilizer is unnecessary.

I get the part about not masking the problem before you fix it, but disagree with your opinion that a stabilizer is "unnecessary" unless you specifically know how and/or where he rides.  I'm an intermediate rider and adding a Scott's stabilizer to my WRR has been a game-changer for me.  I can now ride tight steep rocky root-infested single track that I couldn't ride before on this bike.

It's not about "pushing the bike hard" or doing things "unusual".  I'm just a regular 50 year old guy who wants to enjoy riding my dirt bike where the other dirt bikers are riding.  A steering stabilizer makes a measurable difference to that end, especially considering the extra weight of the WRR compared to WRF etc.  Sometimes the difference in deflection absorbed by the stabilizer is the difference that keeps the bike on the trail and the mountain.

I rode this trail last weekend and had a blast, thanks in part to my stabilizer.  Better riders can probably ride it fine without a stabilizer, but for me it was "necessary". (This video is from someone else's ride on the same trail.)


Interesting insight, thanks.

-morgan
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Jeff d




PostSubject: The plot thickens   Fri Sep 25, 2015 8:42 pm

So it's pretty much definitely tire/balance related.

Tonight I swapped on the front street tire along with a new tube (to get rid of the dynabeads).  I balanced it and it took 3 1/4 oz which seems like a whole lot.  I have a 7 .25 ounce weight strip on one side and 6 on the other all centered around the light spot.  This makes it such that if I spin the wheel with the brake caliper off it never stops at the same spot consistently. Without the weight it stopped at the same spot every time.

Interestingly it turns out there were already dynabeads in the tires when I bought it.  I didn't know this and added a second "dose".  Still there were only about 2 oz in the tube with the d606 front tire.  Given how much weight it took to balance the street tire I'm wondering if the dynabeads don't work or if there just weren't enough in there.

Rode it and the wobble moved up to 70 mph and was less violent when it was present.

Not sure where to go from here.  Maybe I'll remount the d606 and take them to a shop for spin balancing?  Or double down on the dynabeads?
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66T

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PostSubject: Re: Head shake   Sat Sep 26, 2015 4:43 am

From what you've written, there's no need to take the bike anywhere for balancing. What's already been done is ok imo. And I wouldn't worry about the weights. You should see mine (to balance out the rim lock).
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Jeff d




PostSubject: Re: Head shake   Sat Sep 26, 2015 6:27 am

This morning I swapped the d606 knobby front tire back on (since that's the tire I want on there) and balanced it. It took less weight than the street tire (yes, I had the light spot mark at the valve stem for both). 3.5 oz.

Took it for a ride and the wobble is still there but at about 68-69 mph. At least I can cruise at 65 now which is about the minimum "safe" speed I can go if I jump on the interstate around here. It's more pronounced like before though.

I might buy a balancing stand. I can see that there's enough drag even with the brake caliper removed to give quite a wide margin of error. At one point I put 7 oz of weight on the wheel and that point still didn't consistently end up at the bottom when spun.

I'm tempted to leave the weights on but put the tube with the dynabeads back on there. I'm getting tired of levering tires off/on though. Maybe with the tire+wheel closer to properly balanced plus the dynabeads would do some good?

I still haven't touched the rear tire yet though.
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Ziabeam

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PostSubject: Re: Head shake   Sat Sep 26, 2015 8:58 pm

I cringe when I hear someone say a steering stabilizer is not necessary. True. It ain't. Until a shimmy becomes a wobble, becomes a tank slapper, and a high side. I use to relish and ride through any wobble, on any bike, until the dominos started to fall (the ones outlined above) on a KTM 990 in 2010. Almost killed me. Every bike that sees speeds above 60-65 with a front knobby now has one, and the shimmies are gone. YMMV
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