High speed wobble

[blaxmax]

Yesterday, I took Zveruga out for a ride. It was 40F and I had rode out a mile or two from my house. Started decelerating from about 50 mph and decided to lean back and stretch out my back for a sec. I let go of the handlebars, like I have done many a time.

This is the first time that I have seen the handlebars go from steady to a wobble. At first it was a little vibration and then I saw that the amplitude kept increasing!

Obviously I just clamped back on the grips and that stopped the wobble - very, very freaky.

Here is what I can tell you:
With Progressive springs, zero pressure and Synthetic ATF for fork oil, the front end can be a little bouncy until the oil warms up.

It was cold, so I doubt the tires were warmed up. The road surface was 40F as well.

The bike was decelerating in third gear.

I ended up leaning back a bit, so I shifted my weight (230 lbs) to the back.

I have not experienced this before and I have just gone through the Morely bounce adjustment, new tires, etc, etc.

My thought is that the cold was a factor - both tires and cold fork oil.

Just putting out another data point on the whole wobble thing.

Ps - I have had my bike up to 100 mph both single and two up with no high speed wobble issues. Haven't gotten a chance to go faster yet.




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I'm not so sure that's to do with the cold air.

 

[Specs95t]

I'm not so sure that's to do with the cold air.

Have you had/heard of similar?

 

[blaxmax]

Have you had/heard of similar?

I haven't but cold air will lose a few pounds of pressure. I don't think enough to do what yours is doing.
I would check the steering head bearings.
I can let completely off the bars with a cruise control and it stays in a straight line.

 

[tothemax93]

I haven't but cold air will lose a few pounds of pressure. I don't think enough to do what yours is doing.
I would check the steering head bearings.
I can let completely off the bars with a cruise control and it stays in a straight line.

It would be interesting to see if you got a wobble without the cruise on, decelerating. That's when I would get a low speed wobble.

 

[blaxmax]

It would be interesting to see if you got a wobble without the cruise on, decelerating. That's when I would get a low speed wobble.

I don't. I have no wobbles at all.

 

[DMAN999]

I use a throttle lock (on the highway at 7-80 mph) on long rides and have never had any wobble when doing that.
But I also do the bounce test every Spring and adjust my steering head bearings as needed.
The only time I ever had any wobble it was a low speed wobble (40-45 mph when decelerating) and it was caused by a worn/cupped front tire.
I replaced the tire and it disappeared.

 

[Lotsokids]

I can let completely off the bars with a cruise control and it stays in a straight line.

When I let go of my bars (without cruise control), my bike leans / turns left... slightly. Every time.
That's why I think I have a front / rear wheel tracking issue.

The only time I ever had any wobble it was a low speed wobble (40-45 mph when decelerating) and it was caused by a worn/cupped front tire.
I replaced the tire and it disappeared.

I can verify that comment also! I had that same issue on a different bike (FJ1200). Replaced front tire, problem solved. Seems sort of common.

 

[Lotsokids]

WOBBLE CAUGHT ON VIDEO​

Last couple days were bad "wobble" days. I finally decided to record it with my GoPro.

Here is is. I'm going into town. Yes, I'm wearing shorts - a risk I take on super hot days, but not on longer rides.

Speed when wobble started: About 200 Km/H (124 MPH). Hard acceleration, bumpy road = wobble generator. It felt more violent than the video captured. Watch my right knee in the video.

Here's the video: http://vid5.photobucket.com/albums/y177/Lotsokids/V-Max/New%20VMax/V_Max_wobble_zpsyysjuh9c.mp4

Recap of my maintenance to date:

- Replaced rear tire.
- Replaced original fork springs with Progressive springs. New oil, and zero air pressure.
- Replaced fork brace with HUGE thick steel brace.
- Front tire air pressure is leaking very slowly. Wobble exists at 20 PSI and 40 PSI. Air pressure is not the root problem.
- Replaced upper and lower steering head bearings and races. Tightened with "Bounce" method, then a little tighter.
- Re-torqued swingarm bearings.
- Manual "shakedown" of front and rear wheels. No obvious free play in axle bearings.

I've owned (2) 1985 V-Maxes prior to this one, but no wobble at all on those. And those had the smaller fork tubes than my current 1999 model.

 

[Miles Long]

You should put a photo of your daughter behind your flyscreen.
High-speed wobble issues will never again be an issue.
Cheers!

 

[sdt354]

That looks constant. Run-out, somewhere up front?
Just a reminder to all. When tightening head bearings,the fork get compressed. It's a good idea to loosen the clamps on the trees, shake the forks into alignment, then re-torque the tree clamp bolts. Later style forks-make sure if you slid them up the trees to lower the front, it's equal on each tube.

 

[jfeagins]

Put 'er up on the center stand & video it running so's we can see the back tire/wheel whilst it's spinnin'. 2nd-3rd gear slightly above idle should do it.

 

[Fire-medic]

Hah, a good one, Miles! A reminder about what is precious.

That road looked to be nasty-bumpy! if you did it on a perfectly-graded road, then maybe I wouldn't chalk it up-to the road condition.

I wouldn't use any tighter than spec front end torque for the steering head. If you have it set to Sean's recommendation, that's it, don't go for the tighter setting. Also, try running 10 psi in the front fork, assuming you still have the capacity. For me, running no air vs. being pressurized is a big difference in steering accuracy, compression under under braking, and jounce absorption (the opposite of rebound).

You should put a photo of your daughter behind your flyscreen.
High-speed wobble issues will never again be an issue.
Cheers!

 

[Miles Long]

Hah, a good one, Miles! A reminder about what is precious.

And I wasn't joking about that, Medic.
Years ago, a workmate of mine did exactly that. His irresponsible riding went out the window, and he never got another speeding ticket.
I was also going to comment on the shorts, but figuring that ATGATT usually is your department, I held off. Didn't want to steal your thunder.
Cheers!

 

[Lotsokids]

That looks constant. Run-out, somewhere up front?
Just a reminder to all. When tightening head bearings,the fork get compressed. It's a good idea to loosen the clamps on the trees, shake the forks into alignment, then re-torque the tree clamp bolts. Later style forks-make sure if you slid them up the trees to lower the front, it's equal on each tube.

Yes, I believe there is something to that. Like I've said before, I think I have a front to rear wheel tracking problem. Because of the way it acts, (leans left when I release the bars), I think the front wheel wants to move a little right compared to the rear. So obviously on rough roads and/or hard acceleration, the front gets light and wants to drift to the right creating a wobble.
Just thinking out loud. I'm not a specialist.

By the way - No wobble on the drag track. Maybe a couple times, but very, very minor and completely controllable.

 

[Tex85]

Hah, a good one, Miles! A reminder about what is precious.

And I wasn't joking about that, Medic.
Years ago, a workmate of mine did exactly that. His irresponsible riding went out the window, and he never got another speeding ticket.
I was also going to comment on the shorts, but figuring that ATGATT usually is your department, I held off. Didn't want to steal your thunder.
Cheers!

It does work, it has kept me in line for the past year. Thanks again Miles!

 

[Miles Long]

It does work, it has kept me in line for the past year. Thanks again Miles

!

Your'e welcome, Tex. We all like to have fun on two wheels, but no reason that we have to kill ourselves doing it.
Lotsokids- now that I'm done ranting, I'll comment on the wobble thing......
- as I suggested before, remove that big-*** fork brace , install the OEM, loosen and then tighten all the upper and lower tree bolts, as others have suggested(particularly after replacing the steering neck bearings) Doing this will insure that there are no stressed points in your front end.

Removing a heavier fork brace? - without getting into a long explanation - trust me - sometimes too much stiffness is a bad thing. Won't hurt to try it.
Then do a test ride. Wearing suitable clothing.
Cheers!

 

[jfeagins]

.... - without getting into a long explanation - trust me - sometimes too much stiffness is a bad thing. ... Cheers!

The commercials say to report any stiffness lasting more than four hours to your doctor immediately. :biglaugh:

 

[Miles Long]

The commercials say to report any stiffness lasting more than four hours to your doctor immediately. :biglaugh:

Good one, Jim! I knew that was coming eventually.......no pun intended.
Cheers!

 

[Lotsokids]

MOST VIOLENT WOBBLE TO DATE​

I rode conservatively for 4 hours yesterday. No wobble at all.

But I rode to work today and the wobble showed itself... many times. EVERY TIME in two corners, hitting a couple known dips in the road, at steady speed - about 65 MPH. So not necessarily only during acceleration. There is one area (location of my previous wobble video) that is notorious for generating a wobble. It's a bumpy road with some issues in the road surface. But it's long, straight, and open - hard to not hit the throttle.

So today I hit it, and when I reached about 70 or 80 MPH the beast immediately started a VIOLENT wobble. I don't know the proper way to respond other than "white-knuckling" the handlebars and riding it out. But today was different. It was bucking so hard, it bounced vertically OFF THE ROAD. It was very literally like riding a bucking bronco. It was all I could do to keep it vertical, but I did. I could feel both tires leave the pavement a couple times. I was all over the place, but didn't crash. That was just crazy.

The strange thing is that it's not consistent. Some days are better than others. Today was CERTAINLY a bad day!

I'm left with nothing else to check, and nothing else to change other than major components like swingarm, frame, or forks.

One thing is consitent - No wobble on a flat, smooth surface... like the drag track.

 

[Tex85]

Looks like you had a good exercise in sphincter control today! Glad to hear you were able to keep it vertical, I imagine it was quite the adrenaline rush.