Front End Wobbles

[Alex]

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

and

http://www.ninjette.org/forums/showthread.php?t=13288

[Jono]

http://faq.ninja250.org/wiki/My_bars...e_my_hands_off

[leed]

I changed my front tire at 9000 miles (stock IRC). It wobbled at that point. My fresh tire (GT501) has been on for 600+ miles with no signs of wobble. When I was uninstalling/installing my old/new tire, I noticed that my old tire had begun to cup, and I feel that given the asymmetric tread and my love for hard braking, that the cupping of the tread may have been instigating the front end wobble. Who knows, though.

[Dragone]

hmm, as mentioned, cupping of tires from crappy weak suspension, lost wheel weights will cause this issue.

edit: double check axle install torque and caliper/brake spinning freely.

[Malicious Logic]

Originally Posted by alex.s

maybe you shouldnt take your hands off the bars?

[Alex]

/merged

[Bill E Bob]

I'd like to find the adjustment for the head bearing. Can someone direct me to the preload numbers. Maybe different preload will change the characteristic. Also I'm wondering if the rear shock adjustment has a bearing on the shimy.

[gilmorec61]

Hey all, i just have a quick question. Recently ive noticed that if im going down the road at say 50 mph, then just take both hands off the handle bars, the front end likes to wobble. I think it always did it, but recently its gotten worse. No, its not enough to cause problems, its just irritating. When i put my hands back on the bars, they stop wobbling, so its not like its a huge force. I havent wrecked it or hit any curbs since ive had it. Im thinking possibly tire pressure, or misaligned forks or something of that matter.

Suggestions?

Thanks, Chris.

[Avenged7Fold]

Originally Posted by gilmorec61

Hey all, i just have a quick question. Recently ive noticed that if im going down the road at say 50 mph, then just take both hands off the handle bars, the front end likes to wobble. I think it always did it, but recently its gotten worse. No, its not enough to cause problems, its just irritating. When i put my hands back on the bars, they stop wobbling, so its not like its a huge force. I havent wrecked it or hit any curbs since ive had it. Im thinking possibly tire pressure, or misaligned forks or something of that matter.

Suggestions?

Thanks, Chris.

Mine does the exact same thing, but with one hand on the steering wheel also. Easy way to stop the wobble is to put both hands on and accelerate. If you find out how to fix it, PM me!

[ThFreakNRican]

heres a little advice from a man we all know and love.

M13!

skip to 2:00 where he gets to the point.

Link to original page on YouTube.

[DaBlue1]

Some wheel wobble/shimmy is natural. It is a spontaneous steering oscillation of the front wheel that usually occurs at a predictable speed when riding with no-hands. It is simply the front wheel trying to stay straight as it is being pushed along. Once you remove your hands from the bars the front wheel has nothing to stabilize it, so your arms act as natural stabilizers.

See- http://en.wikipedia.org/wiki/Speed_wobble (In Two Wheeled Vehicles)

[Alex]

/merged

[dubojr1]

I have a buddy with an 08 that he said did a similar shake when he was decelerating while hands free. At the time we were also discussing switching him over to the Bridgestone BT-016's. After the change he now claims the tire change cured the issue.

[CZroe]

Changing tires has always solved it for me... for the next few thousand miles. It comes back relatively early in the life of my tires!

[dubojr1]

My buddy probably only does a few thousand miles a year so tires would be hard to prove as a fix with his limited mileage.

[devinjc]

Revisit: Early miles no wobble (see posts early in thread) over time I'd pick up a pretty gnarly shake at various speeds if I took my hands off the bars. New tires yesterday and I remembered this thread on the way home, hands off from 80 to 30, no wobble, no shake, no shimmy.

[Bill E Bob]

My '09 developed a bad head shake when I was in Winnipeg last year, at about 20,000 kms. Got a new front tire and it reduced it slightly. Listening to this conversation, I now think that a new back tire as well would have solved the problem.
Now I have a 2011 with just 1400kms and will be anticipating the headshake at 20000, and timing my tire replacements to hopefully coincide with it.
billEbob in Kingston

[thomason2wheels]

Originally Posted by BlueTyke

I thought 250's normaly did that when you were doing the "Look Ma no hands" manuvering... Tyke certainly always has even at lower speeds.

I thought i was the only one here to know about and have lived through the look ma no hands trick...welcome to my world lol.

[thomason2wheels]

Originally Posted by CZroe

Changing tires has always solved it for me... for the next few thousand miles. It comes back relatively early in the life of my tires!

Interesting stuff.....my vstrom has a wobble from about 20 to 50 mph. Above or below that, no issues. If left to its own druthers, the oscillation amplitude gets larger and would turn into a tank slapper if i allowed it to. Amazingly it takes very little effort to damp out the movement. I just dont ever ride no handed. Problem solved.

Given that it causes me no trouble, what about the ones you see on race bikes that literally shake the rider off? How the heck does that happen and turn into the violent things weve all seen? Is it rider error to fail to damp it out witharms and hands earlyin the process or does it happen so quickly there is no time to react?

[Greyfox]

I changed to a brand new tire and aligned my rear wheel correctly. It solved the problem

[old3]

Good news!

The 2013 300 Ninjas have the same wobble!

I found this thread while searching for a solution, figured that tapered roller steering head bearings would do the trick. Still thinking about a full front end conversion to match my GSXR rear shock.

[alex.s]

maybe try rebalancing the wheels before you go disassembling the entire front end

[Alex]

I haven't experienced the wobble yet with mine, but I haven't worn down either the original or replacement tires yet. I had thought that the more relaxed rake would make it somehat less wobble-prone, but seems like it's not wobble-proof yet.

[old3]

Originally Posted by alex.s

maybe try rebalancing the wheels before you go disassembling the entire front end

I've tried the original tire again, balance beads in and out, no difference. I think it is the bearings allowing the stem to walk a little. My front end already came loose and I've retorqued it twice. Bike has 1300 miles. I think I'll be chasing the front end for as long as it has the loose ball bearings in it.

If it was wheel balance it would be there regardless of decel. At 47 MPH it would shake with a light touch on the bar, like 2 fingers to hold throttle. I've done that, it needs to get loaded by decel to happen. That points me towards wimpy fork tubes/bushings, which it has, or wimpy bearings which it also has.

No decel wobble till it gets to 50 MPH, then it goes nuts. At 40 MPH it isn't there. At 90 MPH no issue. Like I said, my ZZR1200s both did the same thing, same speeds too. big, heavy bikes with relatively thin fork tubes and caged ball bearing steering heads.

[alex.s]

you have tried using balance beeds... how about a real method to balance the tire?

when decelling the rake is pitched forward so it is more unstable.


even if the bearings were shot it wouldn't do what you are describing. and having smoother bearings would do nothing but exacerbate the issue since there is less damping being applied to the steering


if you read through the thread you will notice a pattern... old tires wobble more, then people replace them with brand new, fully balanced tires and the wobble goes away. its not coincidence.

also i'll say again, balance beeds do nothing to actually balance the tire.

and before we get into a "they do work, i noticed a difference" debate; if they worked, OE manufacturers, tire shops, racers... everyone would use them. but they don't work, so nobody does.

[old3]

I agree they are useless, and they sit in my original 400 mile IRC in the garage. I've also been riding 17" tired bikes for 2 decades without balancing any of them. My ZZRs both did it with factory original, new and balanced tires. My recently departed KTM 950SMR went thru 3 sets of tires, none were balance after the original set and none did this wobble. My KTM 530 with unbalanced supermoto wheels doesn't shake either.

Your point about bearings and how they carry the load I don't understand. Tapered roller bearings have more surface area and stability than a loose ball bearing. Tey don't have a single point of contact like a ball.

[alex.s]

haven't balanced a tire before but have the same issue on other bikes... but see no need to balance in the future. interesting deduction.

not sure what point you are trying to illustrate with bearings... less friction on the head would make small oscillations turn into bigger oscillations easier in an unbalanced system. bearing drag, or the lack of bearing drag would not change the fact that your wheel is out of balance causing the imbalance in the first place.

i'm sure you've got way more experience than me. (i'm guessing from your post about 2 decades worth) but don't be quick to dismiss young whipper snappers. i love when i go talk to old school harley cruisers that tell you counter steering is bullshit and how they only use the rear brake because if they use the front you'll go flying over the handlebars. but you say you have never balanced a tire and are talking about stem bearing drag causing wheel oscillation. scary dude.

[old3]

Those other bikes did it right out of the showroom. The first ZZR1200 I actually turned around before getting it home. My experience in lets see...34 years of riding/racing has me believing that wheel balance is BS for speeds under 100 MPH. I know what imbalance feels like, I ride bikes with rimlocks and at 40 they shudder right up to whatever speed you dare ride to.

The bearing loads in two directions at the steering head. A tapered roller better controls the loads without deflecting. One theory about these decel wobbles is that the stem is wobbeling in the head as the bearings allow it to "walk". It doesn't take much deflection at the bearing to start the frequency.

I agree with you that to completely dismiss the balance I should just try it, and I may, but I'm 99.9% sure this is a bearing issue. The steering head came loose at 1000 miles. I noticed this wobble after that but like I said, I've had this before with balanced tires and without.

[alex.s]

ok. i'm sure you have plenty of knowledge about plenty of bikes. let me simplify what i'm trying to say;

i have personally seen 3 seperate ninja 250s (not counting other reports on this thread) go from heavy decel wobble to no detectable wobble simply from new balanced tires. ... with absolutely no change to steering stem, head, or any bearings or anything else. you say you have had plenty of issues with all of your bikes... i believe you have said you go to the same dealer every time... if your head stock wasn't tightened properly, what makes you think that punk 19 year old doing setup service balanced your tires properly? IIRC the bike comes from kawi with no fluids or tires right?

[old3]

The steering heads and front ends are fully assembled by Kawi. They don't touch that, on the 300 I think they need to bolt on one handlebar. The bikes are full of fluids except fuel, they test them on a dyno at the end of assembly line.

Old, worn tires that have cupped can also cause the decel wobble. That is why new ones solve some of these complaints.

Some bikes have it brand new, some tires bring it out on others, Triumphs and V-stroms seem to commonly get wobbles from certain tires. Contis in particular and that is the brand I have on the 300 now. That was why I swapped the original 400 mile old IRC back on.

I'll see if I can find the time to get a wheel balancer set up just to rule it out completely.

[alex.s]

if your wheel bearings aren't shot, two jack stands and the axle is enough to balance the wheel along the rotational axis

[alex.s]

Originally Posted by old3

The steering heads and front ends are fully assembled by Kawi. They don't touch that, on the 300 I think they need to bolt on one handlebar. The bikes are full of fluids except fuel, they test them on a dyno at the end of assembly line.

you might want to look at this: http://www.ninjette.org/forums/showthread.php?t=118416

dealer setup and inspection proceedure including checking torque on the steering stem bolt

[old3]

But the threaded nut UNDER the triple clamp sets the bearing tension. That bolt was still tight but the bearings were loose after 1000 miles. Adjusting the bearings requires the removal of that bolt, the triple and setting the load with the collar nut.

That 19 year old $7 an hour (if that) kid isn't supposed to check bearing thrust/play.

[alex.s]

maybe the 19 year old $7 an hour kid checked to make sure it could do wheelies on the post-setup ride check and jacked up your head bearings? because my 30k mile well abused racebike has original oem bearings and has virtually no stem/head play, along with no wobble when the tires are balanced. it did wobble from the factory with stocker IRC tires and only stopped wobbling after i changed the tire and balanced it myself.

maybe the wheels/tires come unbalanced from the factory

[old3]

I left the house at 7:15 with new found motivation. Snow by morning and I headed to Harbor Freight to pick up a balance stand and a pack of 1/4 oz adhesive weights.

At 9pm I was testing the bike with balanced wheels. I fully expected to have some crow to eat to be honest. Shoot my mouth off and what else could happen?

The result is the same. 50 MPH no hands decel wobble despite the balanced wheels.

I'm glad yours is good, wish I was wrong when I said I was 99.9% sure but unlucky me I was dead right!

The dealership I use is where I buy all my MX/off road racebikes. The owner, a +50 year old good guy, is who test rode my bike to help him guide new sales of it. I bought it sight unseen and still to be delivered. They can wheelie KTMs and Huskys all day long, I doubt the Ninja 300 is a big deal to clutch drop into a moped wheelie! They couldn't believe I was even buying one based on my bike history thru them.

[v2Jay]

i had the same problem a few months back and just decided to tighten up my head screw/nut and that seemed to have solved that problem totally. u have to use a long large flat head screwdriver and a hammer to do this so be careful.

[jamg1coco]

ha ve a 2009 ninja 250r I have done quite a lot of mods to it but one problem I can't seem to fix I have death wobbleI I have put new tires on it done fork seal tightened triple clamp head nuT stabilizer new bars when I redid my Fork Seals I put in 5 Woil 360ml should I add more should I redo the oil With 10 W oil how much oil do you recommend using360 mm usually goes around 12.30 ounces Is that 2 little or 2 much oil any help here would be greatly appreciated

[csmith12]

Welcome vijay & matt

[jamg1coco]

Went back and checked through all the stuff that I did I found out that by adding 5 mils of more fork fluid it made my suspension feel a lot better but I still have head shake so I decided to start spinning my tire and checking my Tires in checking my front suspension again I found out when our local motorcycle shop put on my tires they never clean them out there is either sand or water still in my tire going to take them off this weekend and see if it makes it better if it doesn't I will be pulling my front suspension back off ordering new seals again and going through everything once again maybe I will just add 10 w oil