Handlebars wobble

[Sykes92]

So I noticed today coming back from getting my food on my lunch break, that after around 40mph, if I took my hands off the handlebars they would wobble. As soon as I put a light grip they would stop. Now, I know the simple response would be "Don't take your hands off the bars, duh."

Is this something I should be taking a look at when I get my bike back? My bike is being inspected about 16 miles away from home. And won't be ready until tomorrow.

Only thing I could come up with through google was tire pressure or tire wear (but both tires should have around 3k left). Anything else I should look into? Or is this normal? Like I said it doesn't happen below 40mph.

[JohnnyBravo]

I won't mention tapered bearings.
I don't think I've ever took both hands off... I ride one handed a lot though.

There is at least one thread around on the subject, somewhere.

[VeX]

More often than not it's from the "simple things" like tire pressure, but one maintenance item that will cause that is loose steering head bearings. My 250's been doing that for a little while now I just haven't gotten around to tightening it. Maybe I'll do a write-up on it seeing as it is relevant to all 250's.

[Sykes92]

Oh okay, well as long it wasn't anything too serious.

The bike I have was babied by the OG owner and well-taken care of by it's 2nd owner. But I still had a laundry list of stuff I wanted to do, regardless.
I'm hoping to:
- Clean the carbs
- Clean the airfilter/box
- Fresh Brake Pads
- Rejet (not sure if was done to account for aftermaket slip-on)
- Adjust valves
- Change oil & filter
- Change tires in the spring.


So if there was anything else, I figured I'd add it to the list. Ill write down to check the bearings too.

Originally Posted by JohnnyBravo

I don't think I've ever took both hands off... I ride one handed a lot though.

I usually keep both hands on there haha, I only did it out of curiosity.

[JohnnyBravo]

Originally Posted by Sykes92

I usually keep both hands on there haha, I only did it out of curiosity.

Now I'm curios ( why doesn't that look right? ) curious?
When checking out your bike always start with the simplest thing like saves ya time and money
I've heard tires out of balance, and something about the bar end weights as well... That's about the only 5 answers I can think of

Tire pressure
Tire wear
Tire balance
Bar weights
Head bearings

[Motofool]

Originally Posted by Sykes92

..........Or is this normal?.........

http://www.ninjette.org/wiki/Front_End_Wobbles

http://www.ninjette.org/forums/showthread.php?t=121404

[old3]

If you want to fix it, and your tire isn't cupped causing this wobble, read here;

http://www.ninjette.org/forums/showthread.php?t=119551

The stock steering bearings on these bikes are a joke. It seems a matter of pride to deny that in this forum for some reason. I don't get it.

Add "All Balls" steering bearing to your list IMO. My kids 2012 250 had steering bearing failure at around 800 miles as I recall. I fought to find my wobble for several hundred miles if not 1000.

Tightening them won't fix it. They are super cheapo and the races will probably be badly scarred if they were loose. There are pics at the Ninja 300 sight of bearings at 1000 miles with trashed races. They can't function correctly like that, no matter how tight you turn the collar.

Even at their best, they don't give good control and location of the steering stem. Inferior loose ball bearings as opposed to the proper caged balls or the tapered roller bearings. Garbage.

[JohnnyBravo]

We really do have crappy head bearings

[Sykes92]

Originally Posted by JohnnyBravo

Now I'm curios ( why doesn't that look right? ) curious?
When checking out your bike always start with the simplest thing like saves ya time and money
I've heard tires out of balance, and something about the bar end weights as well... That's about the only 5 answers I can think of

Tire pressure
Tire wear
Tire balance
Bar weights
Head bearings

Originally Posted by Motofool

http://www.ninjette.org/wiki/Front_End_Wobbles

http://www.ninjette.org/forums/showthread.php?t=121404

Originally Posted by old3

If you want to fix it, and your tire isn't cupped causing this wobble, read here;

http://www.ninjette.org/forums/showthread.php?t=119551

The stock steering bearings on these bikes are a joke. It seems a matter of pride to deny that in this forum for some reason. I don't get it.

Add "All Balls" steering bearing to your list IMO. My kids 2012 250 had steering bearing failure at around 800 miles as I recall. I fought to find my wobble for several hundred miles if not 1000.

Tightening them won't fix it. They are super cheapo and the races will probably be badly scarred if they were loose. There are pics at the Ninja 300 sight of bearings at 1000 miles with trashed races. They can't function correctly like that, no matter how tight you turn the collar.

Even at their best, they don't give good control and location of the steering stem. Inferior loose ball bearings as opposed to the proper caged balls or the tapered roller bearings. Garbage.

Oh alright wow, thanks for clearing that up for me guys . Ill add that to my list and also probably just keep my hands on my bars too haha. I was just curious of how the bike reacts. I used to ride without using my handlebars on my bicycle all the time (not that I would even dream of trying on a motorcycle) so just curious as to the physics lol.

[JohnnyBravo]

[Motofool]

Originally Posted by Sykes92

Oh alright wow, thanks for clearing that up for me guys ................I used to ride without using my handlebars on my bicycle all the time...........so just curious as to the physics lol.

You are welcome

The lesser mass of the front wheel-steering system of a bicycle makes it less likely to happen, but is still possible, like for any oscillating system (the steering system and the contact patch of the tire act like a pendulum).

It happens to airplanes too, a rapid oscillation being called flutter of the lifting and control surfaces.

These oscillations of the handlebars are the reaction to an off-center disturbance.
They can die out by themselves or they can grow stronger (resonance = tank slapper), depending on the natural frequency of the system.

If still interested, check these out:

https://en.wikipedia.org/wiki/Resonance

http://www.ninjette.org/forums/showt...t=tank+slapper

[old3]

Expanding on that previous post, if the steering bearings don't securely locate the stem, those oscillations are amplified. The "loose" balls don't cover the area equally, rather they randomly fall where they may around the race, and independently of what the top or bottom ones are doing.

It is as if they designed this bike to wobble. It is the perfect storm. Tiny fork tubes, poor bearing choice and a good amount of vehicle weight. Flex away!

[csmith12]

Originally Posted by old3

The "loose" balls don't cover the area equally, rather they randomly fall where they may

That's what she said! Lol too easy!

[JohnnyBravo]

[old3]

Loose balls = a wobbly stem!

[csmith12]

Originally Posted by old3

Loose balls = a wobbly stem!

[notsofast]

I got sucked into this thread at work and lost about an hour. The breakroom is cold...

[JohnnyBravo]

Originally Posted by notsofast

I got sucked into this thread at work and lost about an hour. The breakroom is cold...

it wasn't lost, was spent researching

[JohnnyBravo]

I don't want no wobbly stem, an mine hasn't wobbled yet thankfully!

[old3]

You have much stem stabilizing experience?

[Motofool]

Originally Posted by old3

Expanding on that previous post, if the steering bearings don't securely locate the stem, those oscillations are amplified. The "loose" balls don't cover the area equally, rather they randomly fall where they may around the race, and independently of what the top or bottom ones are doing.

It is as if they designed this bike to wobble. It is the perfect storm. Tiny fork tubes, poor bearing choice and a good amount of vehicle weight. Flex away!

Very true !!!

I had a 150 cc motorcycle that was a nightmare regarding steering wobbling.
At times, I couldn't control the thing even with both hands on the handlebar.
I tried everything that I knew back then, all resulting in no improvement.

I finally found out that the balls of the steering bearings had made little craters on the tracks.
The weight of the bike made the balls try staying in those craters, fighting the normal steering adjusting oscillation.

It was funny to see how the whole steering tried to adopt those fixed positions when left alone (it looked like something magnetic), while the bike was on the center-stand with the front wheel in the air.

Once I replaced those bearings by new ones, the whole problem disappeared.