Handlebar wobble (it's not what you think)

[phroenips]

Riddle me this, Batman.

About 4000 miles ago, I got a brand new PR2 front mounted, and I noticed a handlebar wobble between 40-50 (awfully similar to a worn tire). I was getting ready for a big trip, which would include a visit to GP Suspension to work their magic. I attributed it to possibly worn forks.

After the fork upgrade, it was a little better, but still persisted. Ok, the tire probably got cupped beyond recovery already.

Fast forward to now, trying out a new Bridgestone BT-023 GT. Except the wobble is still there! I checked the fork suspension settings to ensure they matched, no play in the steering head, and double checked all torque settings. I had the wheel balance checked at two other dealers, and they say it's balanced.

I'm at a loss of what to check next. Help?

 

[GalaxyBlue]

Ahh... LOVE these NEPRT Tire Thread!

Do you ride with the factory Yamaha Top Box? Try removing it and see if it goes away. That was my cure WAY back when i had Avons, And i didn't have the problems with any Michelin tires.

YMMV, Of course.

 

[Bustanut joker]

Not sure if that's what's ailing it.. But my topcase causes the same commotion.

 

[ionbeam]

Using a dial gauge check the rims for lateral and radial run-out on both sides, front & rear. Check the tires to see that the bead line spacing is the same on both sides of the tire and that the bead line is even all the way around the tires. Confirm that the tire pressures are OK (in the 40-44 psi range). Check that the fork tubes are both the same height -- just about flush with the top of the triple tree. Have you set the suspension for pre-load and dynamic sag? Have you changed seats, windshields or bar risers? As others have mentioned, a trunk will cause that.

If a very light application of hands damps the oscillations there is nothing to worry about, keep your hands on the bars and just ride.

 

[charismaticmegafauna]

Riddle me this, Batman. ...handlebar wobble between 40-50 ...persisted.

...new Bridgestone ...wobble is still there!

I'm at a loss of what to check next. Help?

Do you ride with the factory Yamaha Top Box? Try removing it and see if it goes away. That was my cure WAY back when...

...my topcase causes the same commotion.

...check the rims... Check the tires ...

...tire pressures...

Check that the fork tubes...

...set the suspension...

...changed seats, windshields or bar risers?

...a trunk will cause that.

Less rear weight bias and more front weight bias -- needed.

Un-load or remove your tour-pak. Raise and/or stiffen the rear suspension. Lower and/or soften the front suspension.

Use a tank-bag. Lean forward when riding (as opposed to Laz-Y-Boy -- feet forward -- 'Murican'-style).

They don't "all do it"... :blink:

 

[TomInPA]

When I had this on my last bike, I installed new Timken tapered bearings into the steering head. Really stabilized the front end and made the wobble go away forever. The FJR loads up a lot of weight and stress on the steering head, and the OEM ball bearings are not very impressive to me. Here is a thread where "I'mAllIn" installed these bearings in his FJR. I'm certain this is something I will do next winter. It made a huge difference in my last bike.

More links:

https://www.fjrforum.com/forum/index.php?showtopic=23222

https://www.fjrforum.com/forum/index.php?showtopic=124441

https://www.fjrforum.com/forum/index.php?showtopic=114432

Do you see a theme here?

 

[Auburn]

Did you check the wheel bearings? If there is any slop there you will feel it in the handle bars. Alos, you may need to add a little rear ride hieght or drop the front end a little to wieght the front end a little more.

 

[phroenips]

Ahh... LOVE these NEPRT Tire Thread!

Do you ride with the factory Yamaha Top Box? Try removing it and see if it goes away. That was my cure WAY back when i had Avons, And i didn't have the problems with any Michelin tires.

YMMV, Of course.

Aren't they great? Oh, I mean, I'm supposed to get all in a huff that my post got moved to a place where nobody will read it, right?!?!

I'm pretty sure I had tested it before, but just did it again. Removed my top quality sears topcase, and the problem persisted.

Using a dial gauge check the rims for lateral and radial run-out on both sides, front & rear. Check the tires to see that the bead line spacing is the same on both sides of the tire and that the bead line is even all the way around the tires. Confirm that the tire pressures are OK (in the 40-44 psi range). Check that the fork tubes are both the same height -- just about flush with the top of the triple tree. Have you set the suspension for pre-load and dynamic sag? Have you changed seats, windshields or bar risers? As others have mentioned, a trunk will cause that.

If a very light application of hands damps the oscillations there is nothing to worry about, keep your hands on the bars and just ride.

One of the places I took it to, did check it I think...said it was perfectly straight and balanced. I'll have to take a closer look though (don't have a dial gauge to check the run-out though). Tire pressures are good (40 front, 42 rear), and fork tubes are also the same height. I've set my rear shock sag, but need to fine tune my front...will also work on that later today (and lower front and/or raise rear as the next test). I do have a Russell seat, CeeBailey's +6 tall, +2 wide, and Helibars + risers, but I had those long before these symptoms presented themselves.

They don't "all do it"... :blink:

I'm well aware...mine didn't do it until ~4500 miles ago either

Did you check the wheel bearings? If there is any slop there you will feel it in the handle bars. Alos, you may need to add a little rear ride hieght or drop the front end a little to wieght the front end a little more.

They *seem* ok to me, but then again, I'm not really sure what to look for. Wheel spins smoothly, and I don't hear any "crunching or anything"

Thanks for all the tips guys! :clapping:

 

[gumba]

I quote, "Check that the right end of the front wheel axle is flush with the front fork. If necessary manually push the front wheel axel or lightly tap it with a soft hammer until its end is flush with the front fork." Gen2 Shop Manual p. 4-23 para. 5c. I like to lay a straight edge across and make sure that the axle is just kissing it. Will not correct for a ****** tire, but it will ****** the crown of the road from turning your tire into ****. I also have a Gen1 and it doesn't seem to be so critical.

 

[madmike2]

Aren't they great? Oh, I mean, I'm supposed to get all in a huff that my post got moved to a place where nobody will read it, right?!?!

I'm pretty sure I had tested it before, but just did it again. Removed my top quality sears topcase, and the problem persisted.

Yah...well...many of the veterans here use the "View New Content" trick, anyway, so it doesn't matter where your post gets moved to.

Back to topic.

You THINK one of the technicians checked the wheel run-out. Double check that.

To me, this sounds like steering head bearings and I think Tom is onto it.

Have you had the steering head bearings checked? IIRC, someone posted a while back that his were "dimpled", and after replacing them, he realized he could have rotated the race 90 degrees and re-torqued them.

Just an idea....for when you have plenty of spare time with nothing else to do.

 

[Auburn]

To check the bearings: you need to take the wheel off, turn the bearings with your finger, you are looking for any sloppyness, anything that is not just smooth rotation, any in or out movement. Look to see if they are dry (lack grease) Your finger is a lot more senstive to feeling this directly on the bearing than with the wheel on the bike.

 

[phroenips]

Yah...well...many of the veterans here use the "View New Content" trick, anyway, so it doesn't matter where your post gets moved to.

Back to topic.

You THINK one of the technicians checked the wheel run-out. Double check that.

To me, this sounds like steering head bearings and I think Tom is onto it.

Have you had the steering head bearings checked? IIRC, someone posted a while back that his were "dimpled", and after replacing them, he realized he could have rotated the race 90 degrees and re-torqued them.

Just an idea....for when you have plenty of spare time with nothing else to do.

Count me amongst the "View New Content" crowd

I don't have the proper tools for the steering head myself, so I'll either have to source them, or take it to a (more trusted) dealer. I figure I only have two or three things left to try: double checking the runout, wheel bearings, and finally, steering head. The wheel bearing is easy enough to check...I just need to pull the wheel off. again. sigh. And I'll need to find a friend with some calipers to check the runout while the wheel is off the bike. I have a feeling it's the steering head as well, and if I'm gonna dig in there (or have someone dig in there), I might as well replace the bearings with some tapered. The All Balls kit is all of $30-35 or so. I didn't think they would wear out at only 30k miles, but if they are, I see I wouldn't be the first.

Things I've tried so far: topcase removed, tire pressures confirmed, suspension sag set (front and back), rebound dialed in, slid up the forks in the triple clamp.

 

[rushes]

Yah...well...many of the veterans here use the "View New Content" trick, anyway, so it doesn't matter where your post gets moved to.

Back to topic.

You THINK one of the technicians checked the wheel run-out. Double check that.

To me, this sounds like steering head bearings and I think Tom is onto it.

Have you had the steering head bearings checked? IIRC, someone posted a while back that his were "dimpled", and after replacing them, he realized he could have rotated the race 90 degrees and re-torqued them.

Just an idea....for when you have plenty of spare time with nothing else to do.

Count me amongst the "View New Content" crowd

I don't have the proper tools for the steering head myself, so I'll either have to source them, or take it to a (more trusted) dealer. I figure I only have two or three things left to try: double checking the runout, wheel bearings, and finally, steering head. The wheel bearing is easy enough to check...I just need to pull the wheel off. again. sigh. And I'll need to find a friend with some calipers to check the runout while the wheel is off the bike. I have a feeling it's the steering head as well, and if I'm gonna dig in there (or have someone dig in there), I might as well replace the bearings with some tapered. The All Balls kit is all of $30-35 or so. I didn't think they would wear out at only 30k miles, but if they are, I see I wouldn't be the first.

Things I've tried so far: topcase removed, tire pressures confirmed, suspension sag set (front and back), rebound dialed in, slid up the forks in the triple clamp.

Ride by a few machine shops in your area.

If you find one with a bike or 2 in the parking lot, ask at the office if you could leave a message for the motorcycle rider guy/guys.

Offer a beer or 6 if he'll bring home his travel indicator an help you check your wheel and bearings....

 

[LAF]

All I know is the FJR is not the only bike to present with this phenomena.

Every thing I have read said bad tire or balance, followed by rim true and then of course steering stem bearings.

My LT did it from new on all tires including, 880's, Avon Storm and Storm 2's. The only time it did not was on a Azzaro I acquired, and then a Z6.

I have seen it discussed all the way to harmonics.

My new PR'2 do it. Dont know if the OEM 021's did it, I was afraid to let go of the bars on them

Seems it is a crap shoot unless you truly do have a wheel bearing or steering stem bearing problem.

All I have read and experienced is it is for sure a low speed decel wobble that clears up as soon as you hand touches a bar, in most cases

I did have a set of 1/2 worn, talk about road noise singing, hard a$$ 880's go into almost a tank slapper when I first got the bike.

I know at 30K if any bearing was suspect it would be replaced for what they cost. And I would sure have the rim checked to be sure of it.

Hope you get it squared away, and please let us know what you find.

Ohh and my most favorite reply, "just keep your hands on the bars"

 

[phroenips]

Ohh and my most favorite reply, "just keep your hands on the bars"

Yeah, that's a pretty good one

My issue is that I can still feel it in the handlebars...including when riding through the twisties. It somewhat detracts from the road feel, and therefore isn't as much fun. <_<

Last night involved pulling the wheel off. again. Wheel bearings were smooth, and I did find some old calipers I forgot I had and checked the lateral runout. Not sure what acceptable tolerances are, but I only measured at most a .010" variation. I checked the other FJR in the garage, and it was the same. The calipers aren't near large enough to check radial runout. A few spot checks with a highly precise and calibrated tape measure h34r: showed it to be round.

I'm going to go ahead and upgrade to tapered steering head bearings. It's never been serviced (manual calls for every 16k miles), and if I'm gonna be in there, might as well swap 'em out since they're so darned cheap.

If that still doesn't solve the problem, I guess I'll just need to keep my hands on the bars.

 

[Fred W]

Less rear weight bias and more front weight bias -- needed.

Raise and/or stiffen the rear suspension.

Lower and/or soften the front suspension.

Hmmm, I think I disagree with this advice.

My understanding of steering geometry tells me that a steeper steering angle is less stable and is therefore more apt to oscillate with any sort of imbalance, runout or misalignment.

Anything done that increases the positive caster would result in increased straight line stability and less tendency to wobble. This would include lowering the rear height, raising the front suspension (not raising the fork tubes). Raising the tubes would decrease the castor, make the steering less stable, but allow the bike to turn-in quicker. But these things only make the steering more or less susceptable to oscillate. They do not cause it.

In the same vein, steering stem bearings can not cause nor cure the cause of the wobbles. They can only mask it and appear to cure it. If there was no rotating imbalance at the wheel to precipitate the oscillation, your bearings could have zero torque preload, therefore be providing no dampening effect at all and it still wouldn't wobble. But it is a tolerances game of tradeoffs. You will always have some degree of rotating imbalances. Putting some dampening in at the bearing via either preload or using tapered rollers is a way to hide that.

I would suggest re-checking the wheel balance (yourself) and if there is a lot of weight make sure that is split evenly on both sides of the wheel centerline. Shops frequently do a piss poor job of balancing wheels. It's a very easy and simple check if you know someone with a balancing setup.

There is also a possibility that your new tire is not right. Just because it is new doesn't mean it is good. Either not round radially or straight running axially. You can measure the tire runout on the bike, same as you did for the wheel rims.

 

[charismaticmegafauna]

Less rear weight bias and more front weight bias -- needed.

Raise and/or stiffen the rear suspension.

Lower and/or soften the front suspension.

Hmmm, I think I disagree with this advice.

My understanding of steering geometry tells me that a steeper steering angle is less stable and is therefore more apt to oscillate with any sort of imbalance, runout or misalignment.

Hmmm, I'm not so sure...?

Yes, a steepened steering angle (less positive caster) will decrease trail.

But, what's the correct amount of trail? As the m/c sags rearward trail may increase -- maybe too much?

Conventional wisdom may suggest: More trail = more stability?

I'm not so sure...

Raising the tubes would decrease the castor, make the steering less stable, but allow the bike to turn-in quicker. But these things only make the steering more or less susceptable to oscillate. They do not cause it.

Caster is the steering angle and the length of the fork tubes doesn't change it. Only the triple clamps design and/or steering head on the frame can change caster.

Caster or lack of caster (or, the amount of caster) -- along with trail is, I believe, the cause of oscillations.

...steering stem bearings can not cause nor cure the cause of the wobbles. They can only mask it and appear to cure it...Putting some dampening in at the bearing via either preload or using tapered rollers is a way to hide that.

I'm with you here -- I don't think MamaYama put the wrong steering head bearings in the FJR.

 

[LAF]

Ohh and my most favorite reply, "just keep your hands on the bars"

Yeah, that's a pretty good one

My issue is that I can still feel it in the handlebars...including when riding through the twisties. It somewhat detracts from the road feel, and therefore isn't as much fun. <_<

Last night involved pulling the wheel off. again. Wheel bearings were smooth, and I did find some old calipers I forgot I had and checked the lateral runout. Not sure what acceptable tolerances are, but I only measured at most a .010" variation. I checked the other FJR in the garage, and it was the same. The calipers aren't near large enough to check radial runout. A few spot checks with a highly precise and calibrated tape measure h34r: showed it to be round.

I'm going to go ahead and upgrade to tapered steering head bearings. It's never been serviced (manual calls for every 16k miles), and if I'm gonna be in there, might as well swap 'em out since they're so darned cheap.

If that still doesn't solve the problem, I guess I'll just need to keep my hands on the bars.

From what I have read you are in for a treat on those steering stem bearings. While you had the wheels off did you check them for balance? I use a Mark Parnes so I have something when I spoon on new tires. I can tell you the weight amount and placement change pretty good, tire to tire and from one to the next. The 021's had a lot of factory weight on in two different places, and the new PR2 needed less weight and only in one place.

If your psyched to go after that steering stem I am rooting for you, however I sure would be making sure that is what was needed. Also you have checked the rear balance also right? Sometimes rear and front problems collide in confusion.

I am rooting for you man :yahoo:

Can you get any shake or shimmy from the forks with you and someone else having at it? Do you have a mechanics stethoscope you can lay on the stem and listen with? They are very cheap and interesting to poke around with if you really wanna hear some **** when the motor is running

 

[Fred W]

Raising the tubes would decrease the castor, make the steering less stable, but allow the bike to turn-in quicker. But these things only make the steering more or less susceptable to oscillate. They do not cause it.

Caster is the steering angle and the length of the fork tubes doesn't change it. Only the triple clamps design and/or steering head on the frame can change caster.

Caster or lack of caster (or, the amount of caster) -- along with trail is, I believe, the cause of oscillations.

Au contraire, mon amie. When you vary the effective fork tube length, either by sliding the fork legs up in the triple clamps or by varying the spring pre-load, you will be changing the angle of the steering head (and forks) in relationship to an imaginary vertical line (ie perpendicular to the road surface). That is the definition of caster, not the steering stem angle to the vehicle itself. That's why raising the forks in clamps, or raising the rear end, make the bike handle quicker.

FWIW, these changes will also effect the rake and trail to an equal extent.