Fixing the speed wobble on an '85

[Shuriken]

This thread is going to be sort of a progress thread on what I do (probably over the winter) to fix the speed wobble problems on my '85 Max. Not sure how long it will take me to fix the problem or how quickly I can get to it now that winter is around the corner (since it is hard to run 110+ down the road in the winter!) though.

This thread is linked to another I started regarding the handling of my bike. The following turned into a very helpful thread:
http://www.vmaxforum.net/showthread.php?t=4456

So.... for starters, I replaced the crappy worn out IRC tires that were on the bike since I got it. I replaced the IRC tires with Metzeler ME880s on the front and rear.

Just replacing the tires with good ME880s totally eliminated the problem I had with my bike when I would try to change lanes over a double-yellow line, or really, change lanes at high speed altogether.

The IRC tires that were on the bike had a tread groove that ran around the circumference of the tire right on the contact patch area of the tire. These grooves caused all kinds of handling problems, because after I replaced the tires with the ME880s (which do not have any center grooves in the contact patch area), those handling problems went away immediately. (BTW, in another thread, Hobejam advised against tires with those worthless grooves....)

Also, the headshake problem I would encounter upon deceleration from about 45mph was eliminated by the new tires as well. I had a suspicion that the original front tire was crap; installing the new ME880 front proved this theory.

In general, the ME880 tires feel much better all around. They feel like they have a sturdier sidewall and they seem to have fantastic traction.

However, the new tires have NOT solved the high-speed death wobble. I have taken the bike into the 90-115 range many times now on the new tires and the bike will still start the slow oscillating wobble. I consider the wobble to be so unsafe that I will not push the bike any further. The wobble will start anywhere after 90 and only gets worse the faster the bike goes.

The bike is stock, so I haven't raised the forks in the triples or anything like that yet. However, after encountering the speed wobble on the first 60 mile segment of a 120 mile ride today, I decided to let all the air out of the front forks for the return segment. I wanted to see if I could improve stability.

The bike does feel just the tiniest bit less "springy' ... feels just a tiny bit more dead in the front end. Not sure how else to describe it, maybe it's undetectable anyway. However, I still encountered the death wobble over 90mph, so removing the air from the forks didn't do much.

In raising the bike off the front wheel and swinging the bars from left to right against the stops, I can tell the steering head is a bit too loose. As long as this test is a really good indicator.... I get a slight bounce. So I assume that I need to work on the front end to get rid of the speed wobble. And if I am going to work on the front end, I may as well just replace the bearings.

 

[jfeagins]

Did you have the REAR tire spin balanced before re-installing with the new tread? Proper balance in the REAR tire has ALWAYS cured the high speed wobble in my 85.

 

[naughtyG]

So I assume that I need to work on the front end to get rid of the speed wobble. And if I am going to work on the front end, I may as well just replace the bearings.

For what it's worth - on my '86, fitting and balancing two brand new Shinko T230 tires also helped a lot in making the bike feel more planted over bumps and lane changes, but did nothing to help the high speed wobble.
I have stock front forks, they are fitted with Progressive springs and can't be raised in the yokes because of the air valve. I also have no air in them and just replaced the oil with 15 W.
On the rear I have an older set of Progressive shocks (I think) that are 12.5" rather than the stock 13".

I have just replaced my head bearings, and am currently waiting for front wheel bearings. I had tried the Furbur fix and it helped a little, but still wobbled above 125. I tightened the head nuts to the point where the bike would weave at slower speeds, and it still wobbled. I thightened the bearings to where my bars woulnd't bounce off their stops and it also helped a little, but it would still wobble. Each fix allowed me to go a little faster, but only made the wobble that much scarier when it came at even higher speeds!

Then when I dismantled my front end I realised why: having taken off the wheel, forks, bars, headlamp etc, I finally got to feel how bad my head bearings really were by moving the tripple trees only by hand - it was so rough it was obvious they were totally shot! I'm sure you've seen the thread in which I posted the pics of my old bearing? They were smooth to the touch, and the rollers felt fine too, but they were DEAD.

Since putting the new bearings on, I've only been to about 120mph a couple of times, and not for long enough (not on highway) but didn't feel like it was gonna wobble at all. Then I noticed my front wheel bearings were dead too, and I'm still waiting for the new to arrive (hopefully this week). I suggest you check yours when you do your front end too - just stick your fingers in each wheel bearing and spin - if you feel any looseness or roughness at all they need replacing.

As soon as I have mine back together hopefully by next weekend, I'll be back to doing my 90-miles run on the highway, and will report on my progress, but I have a strong feeling that my wobbles will be gone as those old head bearings were completely shot. I believe the high speed wobble is 100% caused by the head bearings becoming worn. Just think - you have a REALLY heavy bike, with ALL its weight on those two bearings - and even more forces whenever you apply the brakes, go over bumps etc, so they're bound to fail in the long run.

I recommend you buy nice OEM ones from Gary McCoy @ Mondak Motorsports - I made the mistake of buying a set on fleaBay (half price) and they came without the lower sealing ring/washer (OEM lower is a sealed bearing), so I ended up having to buy one from the stealers at twice Gary's price! :bang head:

Hope this helps, but gimme a chance to get my ride back on the road and I'll confirm if my wobble has been cured or not. unk:

 

[Shuriken]

Thanks for the posts, guys. They did balance the rear before I put it back on the bike.

naughtyG, thanks for the heads up. I've been following your posts pretty closely as well. I am very interested to know how your bike runs when you change out the wheel bearings. Just my opinion - and I hope I'm wrong - but the wobble thing, at least on my bike, feels like steering head and/or suspension.

I can see how wheel bearings could definitely contribute to or cause the speed wobble. Your changing them out will definitely prove or disprove your hunch.

I tend to think the front and rear suspension on my bike isn't perfect. Since these bikes have a front and rear spring per side, if they aren't working together or damped just the same or whatever, I could see how the wobble could start. In fact, I tend to think my suspension is not damping out the steering movements as much as I think the steering head needs work.

On modern bikes with good suspension, when you turn one direction and then back to the other, the bike goes and returns without aftertaste! What I mean is if you jiggle the bars at 75mph, do they keep jiggling (like the animations of your signature line) or do they stop? On my bike, the front end keeps going for a few seconds afterwards. I think this is not right. I have noticed the same behavior on nearly all bikes that I have ridden that had worn or leaky fork seals.... Anyway, this behavior is far less pronounced and the bike is far more stable the more weight I add onto the suspension. I'm only around 170 in full gear but when I add another person, the bike is a lot more stable.

So my theory is that my suspension is misadjusted or worn out, and/or the steering head needs readjusting or bearing replacement.

 

[jfeagins]

:confused2: I'm not an engineering expert or even close. I think you may be on to something in that the front and/or WHEEL bearings could and probably do have an impact on high speed wobble.

HOWEVER, I have to disagree with the steering bearings as a contributing cause to the high speed death wobble. I know that proper adjustment of the head bearings and also their condition will play a significant role in MINIMIZING a wobble IF a wobble should occur. In fact, the slight, momentary wobbling when changing lanes or road surfaces may be caused entirely by bad head bearings, but the big, notorious high speed wobbling referred to as tank slapping or the death wobble..........I think has other causes.

That wobble has to be caused by one of or a combination of the front and rear tire/wheel combos. For a wobble to happen, one of these must be out of round. By that, I guess I am referring to the alignment as seen from the front or rear of the bike as either are spinning. A visibly bent wheel would be a big time factor. Less obvious would be the ever so slightest of wobble of the tread as the tire becomes worn from burn outs or ordinary wear. I've run OEM dunlops since buying my Max and they are kinda bad about developing the slightest imperfections (side to side) as the tire wears. I'm guessing the inner belting of construction becomes stressed or something. Anyway, when I put on a new tire, the wobble always goes away. I had a front tire get serious cupping and the only problem would be up and down hopping at slower speeds and a more rapid up and down shaking/vibration in the handgrips at higher speeds.

Tighening up head bearings or other head mods like the Furber fix only help minimize and control what is already happening and shouldn't be. If you were to put a small, heavy wheel on a pencil for an axle, give it a big spin you could feel the centrifugal pull on the axle if you try to tilt the axle first to one side, then the other. Now take that same small, heavy wheel and put a slight bend in it and repeat the experiment. Now by spinning the wheel, you'd feel constant side to side undulations.

Try that at speed on a Vmax and amplify it forward from the rear axle up to the front end via the frame, and you don't have to have a visible bend in the rear tire/wheel combo to get a significant amount of force up at the front of the bike just waiting on the right moment to begin tank slapping. All those other tweeks, adjustments, and fixes are just taking medications to hide the symptoms and may not be healing the disease.

Again, I don't come close to being an engineer, but this is what my experience with my Vmax and other bikes before it have taught me.

What do you all think? Am I on to something, or am I growing senile?
:ummm:

 

[naughtyG]

I guess I will find out once I get mine back on the road, and let everyone know the deal.

I have high hopes for the brand new head bearings, but we shall see. No claims here of engineering expertise either, but having had a feel of just how bad my head bearings really were when moving only the triple tree (no wheel, forks, bars etc attached) made me think!
I don't really believe that the front wheel bearings may have had much to do with it, but they could play their part too. Mine just happened to be dead, so replacement was a must. What I noticed when the wheel bearings got a lot worse was a fast side to side shimmy or vibration at any speed if I let go of the bars - something I hadn't experienced before.

When I originally changed my worn OEM Dunlop Qualifiers for brand new Shinko T230s (fully balanced by the stealers), I also changed the old looking 12.5" rear shocks for a pair of OEM 13" shocks, and my wobble went from bad to A LOT worse. So the tires didn't improve it one bit, but apparently the OEM shocks (and/or the extra 1/2" in rear height) most definitely made things worse. When I reverted to the 12.5" shocks (I believe they're older Progressive ones - you tell me http://www.vmaxforum.net/showthread.php?t=5406) things got a little better but by no means did the wobble go away - simply its threshold went higher. By that I mean that with the OEM 13", I would get the death wobble from any speed above 95mph, whereas with the 12.5" shocks, I could go up to about 110/115mph until things got ugly.

But by far, my most odd finding (contradicting what many others have found) was that during high speed wobble, the best remedy for me has been to - as much as humanly possible in the midst of a major Oh Shit! moment - relax my grip on the bars almost to the point of letting them go, and then the wobble would disappear as the bike stabilized itself - all this while slowing down of course! OTOH, the harder I would grip the bars and try to fight it the worse it would get - heading for the tank slapper a little more with every oscillation. I'm just glad I survived so far, to be honest, but it seems to me that putting more weight down on the front made it worse, and conversely lightening the front made it better.
And that, to me, would again point squarely at the head bearings, as if these are worn (as mine were) I believe the rollers could easily oscillate back and forth within the grooves wear created in the races.
That's my theory anyway, practice will prove the point, or not.. :ummm:

 

[dannymax]

I think all the above posts make a lot of sense, but what has me totally baffled is why it is such a problem with the v max.
Every motorcycle is built basically the same, 2 tires & wheels, front forks, steering head bearings, front & rear suspension, etc. All these components are subject to the same stresses, regardless of the manufacturer and any bike that is ridden will wear out the same parts, tires, bearings, suspension, etc.
Why is it that the v max is the only one which has been plagued, consistantly, for 23 years with this "wobble" issue?

 

[naughtyG]

I can only guess, but I think the weight of the bike and its geometry must be adding up to extra stress on components such as the the head bearings that would not suffer as badly on other bikes.

I mean, how many bikes in this weight bracket that do 140mph+ do you know of?

Generally the really heavy bikes (Goldwing, Venture, Harleys tourers etc) are a lot slower. And the faster bikes are a lot lighter.

There, of course, must be something wrong with Yamaha's design, but I don't think it's a problem that's there in a brand new Max - rather it is something that wears prematurely causing all the bikes to eventually get the same problem. Maybe some of the '06 and '07 bikes owners with low miles could chime in and say how much of a high speed (125mph+) wobble problem they have, and if they have none, it would confirm my suspicions...

 

[vmaxfast]

I have a 99, and have had it 135 plus, 4-5 times and over 100 but less than 135 many times, and have never had any wobble problems.( knock on wood). And hopefully will never have the problem.

 

[dannymax]

I also have a '99 and it did have a low speed deceleration wobble (45 down to 35). It had 7K on it then. A small adjust on the head bearings and it is perfect. It now has 13K and no sign of wobble at any speed.

But I know of at least one '07 with very few miles (less than 2K if I remember correctly) that had a wobble. High speed, I think, and the owner sold or traded it because of that, and an electrical issue.

No doubt component wear is the cause in some instances, maybe even most, but there seems to be another cause also. The '07 supports that.
Also very possible it is related to the HP/Weight ratio.

I'm sure Yamaha spent a lot of time trying to figure it out and apparantly didn't get anywhere, now it looks like we may never know for sure.

Wobble on Brothers!! :biglaugh: :biglaugh:

 

[dkw0417]

My 07 had a low speed wobble at around 1000 miles. Tightened it down and all better.

 

[fasterlapdunn]

My 07 had a low speed wobble at around 1000 miles. Tightened it down and all better.

my 07' hasn't had the wobbles yet and I am at 7k. I am going to tighten it down over the winter still.

 

[[email protected]]

My 06 has just over 3K miles. It has a low speed wobble when decelerating from around 60-40

 

[m-cman]

There are eight guys in my riding group that have had or currently have a Vmax. They ranged from 1985 to 2006. Some had the high speed weave and some did not. It seems to me that production line variances may be a contributing cause. I know my 95 had the weave at different speeds depending on the load, the accessories and the tires. It varied from occuring at 95 mph to being OK up to 125 mph which is the fastest I had that bike.The fastest I have had my latest Max is about 115 mph so far. It goes thru several periods of "uneasiness" getting to that speed but no outright weave.

At one time I was going to take my first Max to Computrak (sp?). They put the bike on a computerized jig and actually adjust the frame (by heating and bending or cutting and rewelding) to exact parameters. They are used by some of the Superbike racing teams.Supposedly this makes the bike track exactly with no handling problems. I think they would even add bracing if needed. However, never got around to that as it would have required a trip to Atlanta where they were located at the time.

If anyone comes up with a fool proof, reasonably easy and inexpensive fix, he would get my eternal thanks as that is my main gripe about the Max. :bang head:

 

[naughtyG]

Just to be clear guys - let's talk about the high speed wobble here.

The low speed wobble is similar, but no-where near as dangerous and pant-shitting as the high speed one. And that's the one I'm trying to get to the cause of.

So let's rephrase this - has any '06 or '07 owner here ever experience the HIGH SPEED wobble? (where the bike's head starts oscillating/shaking uncontrollably above 100mph or so and threatening to give ya a big ol' tank slapper)

 

[maxcruiser]

I think that main culprit of the weave and wobble effect on the vmax and pretty much any bike designed in the 80s is the chassis and unfortunately there is no complete fix that will be inexpensive. Of course, there aree things that can reduce the problems, solid motor mounts, better shocks and forks, gussets to the frame, strengthened swingarm, etc... but without alot of cash and work, you will never eliminate all of the ill issues of this 80s designed bike.

Another factor to consider is sitting position. As a sit up or cruiser position, the higher the speed the more wind force and therefore the more upward force on the front end which causes the front to get light and a perfect condition for high speed wobble.

I have looked over the years for a company that would or is building a new frame/chassis for the gen1 vmax with not much success. There is one website that looks interesting, but not a cheap alternative though

http://www.steelheart-engineering.com/

Mike

 

[Shuriken]

I maxed the damper settings on the rears and took it out for a spin today. Unfortunately, I couldn't take the bike up into the "danger zone" as it was getting too late and there were too many cops out. The bike seems to be just a tiny bit less squirrely but again, not sure.

So far I've just taken the air out of the forks and maxed the dampeners. What is lighter weight oil supposed to do up front? That would be another easy thing to do also....

I'm betting that my problem is all in the front end. I just rode my friend's BMW-K1200 again tonight and it balances on a pin and does not jiggle around when you jiggle the handle bars.... there is no such mushy springy quality to that bike in the steering head or front forks at all. At freeway speed on my bike though, if I jiggle the bars, they keep oscillating for a few seconds before stabilizing.

Best way I can describe the way this all feels on my bike is that the shocks are weak, springy, and are not dampening good enough.

 

[dannymax]

Just to be clear guys - let's talk about the high speed wobble here.

The low speed wobble is similar, but no-where near as dangerous and pant-shitting as the high speed one. And that's the one I'm trying to get to the cause of.

So let's rephrase this - has any '06 or '07 owner here ever experience the HIGH SPEED wobble? (where the bike's head starts oscillating/shaking uncontrollably above 100mph or so and threatening to give ya a big ol' tank slapper)

Naughty, I don't recall, did this wobble exist before you put the windshield on? Or, have you taken it off to see if the wobble is still there?

 

[sdt354]

I've got an 89 and just went through the same. Like someone else mentioned, you can't slide the forks up the trees on 80's forks. I ditched the air pressure. dissassembled cleaned,new bushings and seals, progressive springs and a fork brace from the VMOA store. Adjusted head bearings, kept stock pieces in factory order. Went riding Sunday. Dunlop qualifiers with about 6,000 miles on them. Rock solid in the turns and at speed now!

 

[naughtyG]

Naughty, I don't recall, did this wobble exist before you put the windshield on? Or, have you taken it off to see if the wobble is still there?

Yes it did. The first time I rode the bike after buying it, with no windshield, I took it to about 125 and almost killed myself. Having said that, it had dead steering bearings, very worn Dunlop Qualifiers and was missing a collar in the rear wheel assembly! :confused2: