2007 Headshake on Deceleration/Noise in Forks?

[Wingman]

I've searched and read as much as I can find about headshake/wobble in other posts, but I can't seem to find any other low mileage examples of this problem. Many threads about headshake involve cupping, so that is the first thing I checked. There is evidence of slight cupping on the front tire (Metz Z6). The headshake is very mild with no evidence of progressing to an all out tankslapper (yet). It appears when decelerating from 50 mph to a bit above 40 mph. No evidence of any shake above or below that range of speeds, but I do get a bit of wobble when braking moderately at lower speeds. I first noticed the shake around 200 miles. I only have about 250 miles on her due to weather and illness over the weekend (more like a fear of getting more than 20 feet from a bathroom!), but I'm feeling much better now. If it doesn't get any worse than this I can live with it until time for new tires. I have been running 39/41 psi (as delivered) but will be upping this to 42/42 in the morning to see if that helps with the cupping.

I also noticed an audible clunking noise and felt something I would describe as "loose" in the front forks. At first I thought the noise might be the brake pads/calipers moving slightly when the front was pumped up and down with the front brake applied, but neither I nor my brother thought the noise was coming from the brakes. It sounds like it is within the lower fork assembly, as if there is some play between the tubes or something actually loose inside. I plan on chocking the front wheel in the morning and see if the noise/feeling is still present without front brake applied, but I'm guessing it won't disappear. If something is loose in the suspension, it could certainly contribute to headshake if not cause it outright. I was just wondering if anyone elso had noticed anything like this?

I tried pumping the front of the 2002 Honda Magna and it doesn't make the same noise, but it uses a conventional fork rather than inverted like the FJR. I'm wondering if it could be something to do with the valving, and maybe this is normal?

Some info, as it might be relevent:

I'm 6'0", about 230 on the scales, and generally don't ride too aggressively (though this bike would certainly allow much more performance than the Magna once I am more comfortable on her). Rear preload is set to soft and I haven't changed any of the suspension settings yet. The front suspension seems a little firm but not too bad, so I'll probably wait to play with the suspension settings until after I have had time to adjust to the bike a little. The ony modifications to the bike so far is the addition of Skyway's sliders.

Thanks in advance,

David

 

[HaulinAshe]

Not sure exactly what you mean by "finding something loose". But I would be very suspicious of a loose steering head bearing. It has happened before on some brand new '06s. What's to say the same jerk doesn't still work for Yami?

 

[Ignacio]

How about checking the torque of steering head bearings? I searched through your post and didn't see where you check this, and is an extremely common issue.

 

[Inlaw1]

Get used to the wobble, apparently they all do it. Mine does too. With the Metzlers and the Stones.

As to the clunk, it's the linked brakes. One more time: On Yamaha's linked brakes, when you activate the front brake only, three of the four pods for the front brakes are activated. The third one is activated when the rear brake is used. This is the one you hear rattling loose on the pins that hold the pads. If you squeeze the front brake and get someone else to activate the rear brake and rock the bike it won't clunk.

I noticed the same thing when I got my bike and also didn't think it was coming from the brakes. I was wrong.

Wouldn't hurt to check the headset bearing also though, just to be safe. Set the bike on the center stand, have your buddy push down on the rear of the bike bringing the front tire off the ground and grab the forks towards the bottom and try to shake them. If you can move them then it's head bearings.

HTH,

 

[jeremybhm]

I have an 07 with about 1600 miles on it. Until I read a post about the 'wobble' a week or two ago, I hadn't ridden 'hand's free'. So I tried riding with no hands at various speeds over the last week. No wobble unless I go over a bumpy road surface or feature. It's perfectly smooth from 70 all the way down to about 20 where it gets hard to balance with no hands...

 

[TexasFJR]

mild headshake on decel here too on '06 w/ Metz and Avons

 

[SLK50]

The wobble on decel seems most prevalent with Metzler Z6's. Haven't heard similar results from those using Michelin Pilot Roads or Avon Storms. May be due to the wavy center groove or the carcasses' damping abilities at certain speeds. Doesn't seem to progress past a mild weave tho'.

The clunking from the front end may be the floating discs "rattling around" on their carriers. Hold the front brake on and rock the bike back and forth, you'll hear it "clank". I don't think a brake pad would be so loud inside the heavy caliper.

 

[Wingman]

As to the clunk, it's the linked brakes. One more time: On Yamaha's linked brakes, when you activate the front brake only, three of the four pods for the front brakes are activated. The third one is activated when the rear brake is used. This is the one you hear rattling loose on the pins that hold the pads. If you squeeze the front brake and get someone else to activate the rear brake and rock the bike it won't clunk.

Thanks

I hadn't thought about the linked brakes causing the noise, but it makes perfect sense. Seems like a simple bungee cord around my foot and the rear brake pedal would be a simple way to test for sure. I just forgot that there were still 2 pads that were loose with the front brake lever (only) applied.

I will check the head bearing torque as soon as I can get my hands on the tools. Every bike I have owned had at least a little headshake/wobble, so it really doesn't bother me unless it shows signs of progressing instead of damping itself out. My old Honda Nighthawk 750 (1991) was a real tankslapper decelerating through 65 mph. I had the steering head bearings replaced and it got better. When I switched tires from Dunlop to Metzeler it completely went away.

Thanks again,

David

 

[Feejer/Weejer man]

Get used to the wobble, apparently they all do it. Mine does too. With the Metzlers and the Stones.

Have you called each 07 owner and checked about a front end wobble? I will bet you they all don't do it.

 

[AGirl]

Wingman,

I feel your wobblin' pain.... FWIW, my 07 has B-stones, has 3,000 miles (but counting fast), has the wobble symptoms you describe though mine is apparent WITHOUT removing hands from bars, and has a date w/my head-master-mechanic since I'm now back in town since sumthin' ain't right.

AGirl

 

[Inlaw1]

Have you called each 07 owner and checked about a front end wobble? I will bet you they all don't do it.

No, I called every 06 owner.

I'll bet, that sooner or later with the front tire wear every FJR owner will experience some wobble of the bars when letting the bars go upon deceleration.

However, I won't bet much as I could be wrong!

 

[AGirl]

I'll bet, that sooner or later with the front tire wear every FJR owner will experience some wobble of the bars when letting the bars go upon deceleration.

Sorry if I didn't make my post clear, but my wobble is felt w/o even letting go of the handlebars AND I experienced the wobble right out of the gate, er, crate; pinning this issue on tire wear wouldn't be my top hypothesis.

AGirl

 

[Fred H.]

AGirl, you aren't alone. This is a fairly common problem, and is pretty much the nature of the beast. There are things you can do to minimize it, but you may never totally get rid of it. It is caused (IN MY OPINION) by the whirl mode that a gryoscope enters as it spins down and the precession effect from the gryo decays. Spin a childs top and watch what happens as it spins down and enters the whirl mode.

Some things that you can do to reduce it are:

Insure head bearings are tight. Head bearings act as a sort of steering damper, so if they are loose, they will have almost no damping effect. But don't set them too tight or you will end up with a high speed weave due to binding.

Check your tire balance. Also inspect your tires and wheels for runout (out of round condition). Any imbalance will most likely reinforce the oscillations and make them worse.

Cold tires will do it the worst. Don't overinflate your front tire.

Rear loading of the bike seems to also make it worse, as does a top trunk.

Worn, or too soft suspension settings in the front forks can make it worse as well. Increase the pre-load and rebound damping on your front forks a bit.

Some tire brands do it worse than others, mainly due to tread design and how close they are in their QC specs for out of round and out of balance tires from the factory.

Tappered roller bearings will help, simply because they provide more drag and act as like a steering damper.

Keep your hands on the bars when decelerating through this speed range.

I don't know this for a fact, but I get the feeling that the changes Yamaha made in 06 to lengthen the swingarm may have made this phenomenon more pronounced on the newer models.

I have had the problem with both Bridgestones and Michelon tires, though the Michelon don't do it quite as bad.

By the way, if it is any consolation, every single motorcycle I have owned has done this to one degree or another, be it Honda, Kawasaki, Yamaha, or Suzuki.

As for the noise <clunk> that you hear when you apply the front brakes, I can confirm at least on my own bike that this was caused by the rotor moving on the carrier it is mounted to. I can grasp the rotor like a steering wheel of a car, and actually turn it about 1/16th of an inch back and forth and reproduce the exact noise.

 

[Last Chance]

I'll bet, that sooner or later with the front tire wear every FJR owner will experience some wobble of the bars when letting the bars go upon deceleration.

Sorry if I didn't make my post clear, but my wobble is felt w/o even letting go of the handlebars AND I experienced the wobble right out of the gate, er, crate; pinning this issue on tire wear wouldn't be my top hypothesis.

AGirl

AGirl and others,

I, too, have the slight shake/wobble since new. I now have almost 8,000 miles on it. I just got my service manual and a "special" steering head wrench from University Motors. I have had the "shake" on the original Metzler Z6's and my new Avon Storms. Actually a little worse with the Storms. Now all I have to do is find the time to do it.

LC

 

[twowheelnut]

Oy, it's not the nature of the beast. My bike has always - ALWAYS - been dead stable. Worn tires, cupped tires, miss-aligned moon phase and all. In all likelihood, it most probably is related to suspension set-up, failing that, loose steering head bearings or mis-balanced wheels/tires. Improperly inflated tires might do it, too. The design of the bike is solid.

 

[ionbeam]

Oy, it's not the nature of the beast. My bike has always - ALWAYS - been dead stable

TWN, U B A fossil with that '05 of yours. These young whipper-snapper types are talking about '06/'07s. Their rear end ain't like yours :lol: The rear swing arm is longer which *may* alter the characteristics of the beast.

 

[twowheelnut]

I disagree, 'beam. A longer swing arm can only 'help' to eliminate this phenomenon, not exacerbate it. Further, I may be wrong, but I don't think the rest of the geometry changed.

 

[ionbeam]

A longer wheel base should make for a more stable ride at steady speeds, but make turn-in slower. I'm not sure that a longer swing arm implies more or less stability during decel.

The Gen II rear swing arm is longer, but all else remains the same AFAIK, that means that the center of gravity must be different between Gen I and Gen II which will affect stability. The amount of empirical evidence makes it look like something has changed. Guess we need to hear from the ones that have not experienced headshake when new.

The Honda shafties that I've owned all shook, and my V-Max shook. My '04 is the only shaftie that has not had headshake. Me like that a lot

 

[user 213]

Sounds like folks have covered the general issues. One thing, did I miss something on the '07s? I don't recall seeing inverted forks on any FJR. Some new Nissan brakes and different fork legs with the "radial" mounting, but not inverted. :huh: