You do? In that case please enlighten us all. I would love to know how having the forks or front wheel out of alignment would cause oscillation.
Personally I don't believe that it does or can.
Head shake
- Thread starter FJR Bill
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Personally I don't believe that it does or can.
Fork alignment,steering bearing all possible. But when I drove the bike to the shop I had no head shake. Drive away from the shop and I have head shake. Thus my question about what might have been done wrong. Just contacted the shop. They will check it out tomorrow. Appreciate the posted responses.
Thanks, Bill
Thanks, Bill
RadioHowie
I Miss Beemerdons!
Let me pose YOU a question: (using your own words)
"But when I drove the bike to the shop I had no head shake. Drive away from the shop and I have head shake."
So what EXACTLY did the shop do while the bike was in there?
Quoting now from your very first post:
"My 09 has not had head shake until I recently had new PR2's installed."
Seems to me, that's your answer...take the bike back and have them put another tire on it....unless they own up to twisting the frame of the bike testing out their new frame alignment jig.
No.
Steering bearings do not cause head shake. Yes, you can dampen out the shakes by putting increased preload on the bearing, or by using roller bearings, either of which produce more mechanical friction, (or one of those high zoot steering damper assemblies the squids seem to love) any of which will dampen the oscillations, but none of those things cause the oscillation in the first place. Many folks seem to have difficulty differentiating the cart from the horse here.
I say: The things that can cause steering oscillation on a motorcycle are:
1) something out of balance, or out of true, in the rotating mass of one of the two wheel(s)
or
2) anything that increases the steering angle steepness (enough) to increase the instability, and thereby the vulnerability to "normal" amounts of #1.
And that's it. The rest is just a bunch of chicken bone shaking and voodoo.
In order to have oscillation you need to have a periodic (temporal), variable input to the system. Neither mis-aligned forks, nor steering head bearings provide that.
You may say that I am splitting hairs here, but really I am not. With a perfectly true and balanced wheel, we could have zero effort bearings (think how nice would that be) and super steep, quick turning steering angles, with no ill effects.
Steering bearings do not cause head shake. Yes, you can dampen out the shakes by putting increased preload on the bearing, or by using roller bearings, either of which produce more mechanical friction, (or one of those high zoot steering damper assemblies the squids seem to love) any of which will dampen the oscillations, but none of those things cause the oscillation in the first place. Many folks seem to have difficulty differentiating the cart from the horse here.
I say: The things that can cause steering oscillation on a motorcycle are:
1) something out of balance, or out of true, in the rotating mass of one of the two wheel(s)
or
2) anything that increases the steering angle steepness (enough) to increase the instability, and thereby the vulnerability to "normal" amounts of #1.
And that's it. The rest is just a bunch of chicken bone shaking and voodoo.
In order to have oscillation you need to have a periodic (temporal), variable input to the system. Neither mis-aligned forks, nor steering head bearings provide that.
You may say that I am splitting hairs here, but really I am not. With a perfectly true and balanced wheel, we could have zero effort bearings (think how nice would that be) and super steep, quick turning steering angles, with no ill effects.
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ionbeam
2 FUN
Are tires unmentioned but included in #1? Tires are more dynamic than just a rotating mass.
RichDoyle
Well-known member
I've had a number of Honda ST's. If you took your hands off the bars at around 45-50 MPH, every single one of them had a bit of this, especially decelerating down through that speed range. Through collectively a couple hundred thousand miles, numerous sets of tires, regardless of mileage, brand or model, and 16-1/2 years they all did it to some degree or other. I just lived with it, because it was such a limited case. Just putting my hands on the bars, even without any real "grip" would eliminate any trace. And not at higher speeds or lower.
My FJR doesn't do it at all. Only about 3500 miles on the bike so far, so OEM tires FWIW.
My FJR doesn't do it at all. Only about 3500 miles on the bike so far, so OEM tires FWIW.
garyahouse
newbs need the forum
I was thinking of something a little more extensive like the kind of twisting caused by accident damage, not by simple miss-alignment caused by improper assembly or torquing procedure. I was thinking that under extreme circumstances, this could happen. I had a Honda years ago that had some badly twisted forks... enough that the handlebars were noticeably crooked when riding down the road. It did some strange things at speed. I assumed it had to do with those forks. Just an opinion, but maybe not an educated one.
All I do know, Fred, is that my handlebars shook back and forth like a jackhammer at about 40 when decelerating on my FJR with that PR3. It was awful. The day I replaced it, dead smooth, as if there was never anything wrong. My conclusion above was that if indeed symptoms were caused by something being twisted, they would not disappear with the changing of the tire. Therefore shaking was NOT caused or affected by twisted or misaligned forks.
You're saying that they can not do so. You may indeed be right, I don't know. I should add that it would make a lot more sense to me that worn steering head or wheel bearings could magnify this condition caused by imbalance or out-of-roundness of the tire. I was reading just a moment ago while researching this subject and a Dunlop representative called this "tire shimmy," commenting that it was more likely to occur during deceleration.
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Old Guy
Well-known member
The last time this happened to me was years ago and on a Goldwing. But I took it back to the shop, and they replaced the tire. It was a Dunlop Elite 3, but if Dunlop could make a bad tire, I suppose anyone could.
Denver_FJR
Well-known member
garyahouse
newbs need the forum
You're saying, in other words, raising the rear end, compressing the forks, or anything that causes the front forks to be slightly more vertical? This makes sense as this is what happens when you decelerate. The bike noses down and the forks end up being a little more vertical. When I had the problem, it was always more pronounced when decelerating. I wonder if something as minor as increasing front end preload, or lowering the rear end slightly would alter the geometry enough to reduce this effect for guys who have to deal with this because of a bad tire... and don't want to throw the tire out.
You spoke of vulnerability. That word says it all. So you're saying that head shake occurs when front wheel induced oscillations are not dampened or stopped by bearings and suspension components that are operating within their normal design parameters, ei doing their job?? The tire or wheel starts the problem and the suspension and frame components aren't doing their job to dampen it??
Gary
darksider #44
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Yes, absolutely tires are part of the rotating wheel assembly, and being made of rubber, a material that is hard to produce with exacting tolerances, is far and away the most likely cause of oscillation in the front end of a motorcycle (or car for that matter).
Also a part of the rotating mass would be the brake rotors, though they are seldom the cause since they are easily precision machined.
Yes to all four questions. You've got the complete idea .
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SoCalFJR1300
Well-known member
So if you have wobble with a tire then replace it with a new tire and there's no wobble, what has that got to do with alignment??
I've had wobble with a tire on other bikes and replaced said tire and the wobble is gone so I wouldn't call it BS.
Bottom line is there are multiple reasons why you could have wobble....could be bad balance.
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Wow!
I started this thread and it't been very educational for me and I hope for others. I've had head shake at one time or another on just about every bike I've owned. Typically a new set of tires solved it. Also I've never fretted about it because the shake goes away with hands on the bars. What got me was that the FJR never had a head shake, installed new tires and a very uncomfortable shake at 40 MPH.
The rest of the story: Bought the new tires drove home about 10 miles and didn't notice any problems. Next day departed on camping trip with fully loaded bags, trunk, duffel bag on rear seat and tank bag. Not far from home felt the problem and it lasted throughout the 2100 mile trip.
Today, drove the bike toward the shop for them to check it out, they were very willing to do so. However, all bags were removed and the bike had only me on it. I could not duplicate the head shake so I returned home. I think my probably tail heavy loading amplified whatever balance or imperfections of the new tires. I didn't want to bother the shop with a problem that could not be duplicated. I'm not so concerned now as most of my miles on these tires will not be on a fully loaded bike. Thanks for all the helpful posts.
Bill
I started this thread and it't been very educational for me and I hope for others. I've had head shake at one time or another on just about every bike I've owned. Typically a new set of tires solved it. Also I've never fretted about it because the shake goes away with hands on the bars. What got me was that the FJR never had a head shake, installed new tires and a very uncomfortable shake at 40 MPH.
The rest of the story: Bought the new tires drove home about 10 miles and didn't notice any problems. Next day departed on camping trip with fully loaded bags, trunk, duffel bag on rear seat and tank bag. Not far from home felt the problem and it lasted throughout the 2100 mile trip.
Today, drove the bike toward the shop for them to check it out, they were very willing to do so. However, all bags were removed and the bike had only me on it. I could not duplicate the head shake so I returned home. I think my probably tail heavy loading amplified whatever balance or imperfections of the new tires. I didn't want to bother the shop with a problem that could not be duplicated. I'm not so concerned now as most of my miles on these tires will not be on a fully loaded bike. Thanks for all the helpful posts.
Bill
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Queensland Ken
Well-known member
My new Gen3 AEE (same as the ES) showed signs of the "shimmy and de-acceleration “wobble”, riding 500 kms back home from the dealer.
I had the dealer swap out the OEM BT 023 tyres to Angle GT's
I found that the tyres were 35F 35 R and the steering head was loose.
My post on the Aussie Forum, page 7 & 8
I did post that the symptoms have gone, unfortunately they are there, very mild, hardly noticeable.
I also checked the balance, tyre run out, front & rear pinch bolts.
So eventually I'll install tapered rollers some time down the track, in no hurry.
I fitted them to both my 06 and 07, never had any signs of "shimmy and de-acceleration “wobbles” after that.
I had the dealer swap out the OEM BT 023 tyres to Angle GT's
I found that the tyres were 35F 35 R and the steering head was loose.
My post on the Aussie Forum, page 7 & 8
I did post that the symptoms have gone, unfortunately they are there, very mild, hardly noticeable.
I also checked the balance, tyre run out, front & rear pinch bolts.
So eventually I'll install tapered rollers some time down the track, in no hurry.
I fitted them to both my 06 and 07, never had any signs of "shimmy and de-acceleration “wobbles” after that.
garyahouse
newbs need the forum
Ken
Do I understand that you HAD front wheel shimmy with your 06 and 07, but after installing tapered roller bearings, it cured the problem?
Could you shed a little more light with some details?
Gary
Do I understand that you HAD front wheel shimmy with your 06 and 07, but after installing tapered roller bearings, it cured the problem?
Could you shed a little more light with some details?
Gary
Queensland Ken
Well-known member
I was never happy with the 06 until I installed new bearings.
The local dealer tried to tighten up the head bearings just via the 36mm nut, a real joke, never did take the bike back there.
No warranty on them as it is a "bearing" and not covered, so I installed tapered rollers.
A few times I had the dreaded deceleration wobble, nearly turned out to be a tank slapper, twice !!!!
The bearing race was pitted and bits of chrome flaked of the roller bearings. Not good for a new bike.
Never happened again after tapered rollers, 17K kms. Sold the bike @ 135K kms.
Will edit the post and throw up some links and pics.
Bought a second hand 07 with 11K kms in 2011 at a good price in Victoria.
Rode her back to Queensland, 1200 kms, with crook fueling, a crook ECU and a real worn, deformed front tyre, (the rear was replaced).
Terrible front tyre shimmy's and deceleration wobbles, dare not loosen the grip on the controls.
Likewise the race and bearings were buggered.
I replaced the bearings and the bike was fine even with the real crap front tyre still installed.
If I wanted to I could set the MC Cruise and ride her no hands for as long as I wanted, even touch the rear brake to disengage the cruise, no hands, no problems.
Done the install for four friends on the Aussie Forum, no complaints........... yet.
For about $45 a real cheap upgrade for the handling on the bike.
My 07 is still better than the 2014 AEE
From what I've gathered, if something isn't quite right in the first place, like crook tyres or suspension, loose or crook head bearings accentuate the symptoms; maybe due to the steering geometry of the bike ????
The local dealer tried to tighten up the head bearings just via the 36mm nut, a real joke, never did take the bike back there.
No warranty on them as it is a "bearing" and not covered, so I installed tapered rollers.
A few times I had the dreaded deceleration wobble, nearly turned out to be a tank slapper, twice !!!!
The bearing race was pitted and bits of chrome flaked of the roller bearings. Not good for a new bike.
Never happened again after tapered rollers, 17K kms. Sold the bike @ 135K kms.
Will edit the post and throw up some links and pics.
Bought a second hand 07 with 11K kms in 2011 at a good price in Victoria.
Rode her back to Queensland, 1200 kms, with crook fueling, a crook ECU and a real worn, deformed front tyre, (the rear was replaced).
Terrible front tyre shimmy's and deceleration wobbles, dare not loosen the grip on the controls.
Likewise the race and bearings were buggered.
I replaced the bearings and the bike was fine even with the real crap front tyre still installed.
If I wanted to I could set the MC Cruise and ride her no hands for as long as I wanted, even touch the rear brake to disengage the cruise, no hands, no problems.
Done the install for four friends on the Aussie Forum, no complaints........... yet.
For about $45 a real cheap upgrade for the handling on the bike.
My 07 is still better than the 2014 AEE
From what I've gathered, if something isn't quite right in the first place, like crook tyres or suspension, loose or crook head bearings accentuate the symptoms; maybe due to the steering geometry of the bike ????
