Wobble?

[ostringer]

’07 1600 Classic, bone stock. 12,000 odometer.
Experienced a front wheel/fork wobble in 2nd gear – around 15-20mph for about a quarter mile – shook my windscreen & lowers.
Hadn’t ever had this happen since I got the bike early this summer – that day had ridden it 50 mile or so, parked for ½ hour, cranked it back up and started on my way home when this occurred.
Recently paved very flat smooth road. Front tire at correct psi. (I haven’t hit anything, not even a pot hole.)
Figured I’d limp it home, but whatever caused it seemed to go away – drove another 25 mile or so & no issues – start & stop – 0 to 65mph all gears didn’t happen again.
Probably hasn’t had any “steering check” per the Periodic Maintenance Chart.
Sound familiar to anyone? Any typical problems with this model I should check first? Any/all ideas would be appreciated.

(Wanting to ride it this weekend with a “Ride for the Cure” breast cancer group – my first.)

[Sabre-t]

What is the front tire brand and model and what do you call "the correct psi"?

Has the fork oil ever been changed?

Have you checked the torque on the steering stem nut? Has the steering stem ever even been greased? A little maintenance on the steering stem may be all that is needed or the crappy stock steering stem bearing may be worn out or damaged.

There are a lot of things that can cause front end instability and sometimes it is a combination of several things that lead to front end wobble.

[ostringer]

Shinko SR777 130/90B16 HD - 28psi. Tire less than a year old.
Not aware if the fork oil has been changed or if the steering stem has been greased. I have a lift & can perform necessary checks to perhaps diagnose - just want to know of any typ. similar issues for this model bike & where to start. Odd to me it "cleared up" shortly thereafter.

[andyvh1959]

Keep in mind, ALL bikes wobble in a way for the bike to maintain balance and tracking. Most times we never feel it because it is so subtle and fast. At some speeds the harmonics of the tires/forks/chassis/suspension combine to induce an obvious wobble we can feel and see at the handlebar. Heavy bikes from the late 70's were very common to induce the wobble on decel at about 45 to 20 mph. If you kept both hands on the grips you naturally damped it out. If you took your hands off the grips, wobble city! Assuming everything on your bike is correct, perhaps the front tire is the source.

Think of the shopping cart wheel that is fine for tracking until a certain speed. That said, newer bikes have much more stiff frames and better suspension that the decel wobble is much less common. But a heavy bike like a Vulcan may still be susceptible to it. Can't say I've noticed it on my 03 Classic 1600. But I'll be riding it this week so I'll test it at various speeds to see if it does it. I mounted a brand new tire on the 17" Mean Streak wheel earlier this year, so it should be a solid true wheel/tire combo.

[Sabre-t]

I and many others think that the front tire pressure Kawi recommends for these big cruisers, especially the 1700s, is way too low. I've seen comments about it for the 1500s and 1600s, but not as many. I had severe overheating of my front tire on the highway when I ran at 28 psi (and that was on the recommended Bridgestone). Others have had wear issues, especially excessive outside tread wear, which is a symptom of low tire pressure.

Personally, I would increase the front tire pressure to at least 32 psi, especially if you are getting flat patches and outside wear on the tire.

At a minimum, you should occasionally check the stem nut torque. Optimally, you should inspect, clean and grease the steering stem bearings every two years. The OEM bearings are crappy and the plastic cage around the bearings can easily crack. A lot of folks replace them with all metal bearings (All Ball bearings are the most common brand used).

[ostringer]

Sure do appreciate the help/ideas. Gonna inspect the tire for wear & forks for any play asap.

[recumbentbob]

Put 38 psi in the front and 40 psi in the rear.
Running 28 psi I would guess your tire is starting to cup. A cupped front tire will cause a wobble.

[duffy]

My 1500 Classic bagger would wobble occasionally and it was always caused by the front tire, too low of pressure or excessive wear. I ended up running max side wall stated pressure and the tires lasted longer and the wobble was less frequent.

[andyvh1959]

I agree on the tire pressure. I run at least 32 on the front, and actually more often 38 on the front and 40 to 42 on the rear. I get much better wear mileage, far less cupping/scalloping wear, and more consistent handling. A cupped front tire will "hunt" more on surface irregularities, and make any wobble worse.

Even on my BMW R1200RT, which is near 200 lbs lighter than my 1600 Classic, but runs almost the same tire sizes I converted the wheels on my Classic to 17" Mean Streak wheels), I run 38 front and 40 to 42 rear and get very good tire wear, great mileage and no cupping. Low tire pressure, worn out suspension (loss of damping) and improperly setup suspension are the leading reasons for cupplng/scalloping front tires. A lot of people think tire cupping is caused by road crown, riding on the right, making right turns more than left turns, downshifting/braking too hard. Those are very minor contributors, but the major factors are low tire pressure and worn/poorly setup suspension.

[DragonLady58]

Ditto on the above tire pressures....

[Peg]

After experiencing a deceleration wobble fleetingly at around 30mph down to 20mph on both my Nomad and my Voyager, I swapped out the steering head bearings on those bikes from the OEM ball bearings to All Balls tapered roller bearings, and had absolutely no more problems. I'd done the same All Balls installation on the 800 that went before both those bikes, but for a different reason - the steering head bearings on that bike had a flat spot.

[andyvh1959]

Tapered roller head bearings provide a lot more contact area on the rollers versus standard ball bearings. As such there is much less chance for the bearing races to develop flat spots. I plan to update my VN1600 to tapered roller bearings when I rework the front suspension this winter.

Standard ball bearings are more prone to flat spot development in the races. Since we do most riding with the forks pointed straight ahead, each bump tends to hammer the bearing balls into the races. Once that happens the bearing balls want to "settle" into those spots and it restricts the natural action of the forks hunting to self center and balance. When the forks are restricted in any way, the bike reacts by tracking offline, which the riders responds to track the bike back online, but the bike then tracks on that line instead of self centering, and the wobble continues.

Overtight standard round steering head bearings make matters worse.

[ostringer]

Yup – cupped/scalloped front tire left side perimeter.
No play in stem nor front axle.
Aired it up to 36psi (rear to 38) and went on my first benefit ride – no wobble.
Think it will wear evenly now & last for a bit?
Live & learn.
Thanks for the advice!

[Sabre-t]

Once the cupping starts you can expect the tire to wear out quickly. As long as the wobble stays gone, you are probably OK to keep riding on it with the higher pressure, but keep an eye on it. You can be down to the wear bars and even the belts in spots before you know it if you don't watch it closely. And, of course, that bad wear may cause the wobble to return as it gets worse.

[mick56]

" You can be down to the wear bars and even the belts in spots before you know it if you don't watch it closely". You are right there. I had a back tyre that was just plain bald one day. About 100 miles later, and it looked like this.