Front End Wobbles

[dubojr1]

Tested my 08 this morning.... Solid from 90 down to 40. I'll test the 09 SE on my next ride.

[mpdugas]

Somewhere along the line, you mentioned that you had your tires set to the usual 30 psi front and rear. I think the bike requires different pressures than that. I use the K shop manual; the pressure in the front tire is several psi lower than the rear, as I recall.

You might want to check your numbers against your manual.

Once I set my tire pressures correctly on my new 2009, all of my handling peculiarities went away.

[kkim]

there are no "correct" numbers to set the pressures to. what the manufacture states are recommended pressures as a general guide.

you'll find your pressure needs will vary according to a multitude of factors.

welcome to ninjette.

[mpdugas]

Your answer reminds me of a recent purchase I made for my 2005 STi. I left the shop after buying a full set of summer tires for my sooby (which is an annual thing, given the voracious appetite that it has for soft tires) and found that the Discount Tire people had set them to "30 psi all around".

Of course, the car understeered like a pig until I adjusted them back to the 6 pound differential that the shop manual sets forth; sooby needs more in the front than the rear.

I know I can set the tires to presssures higher and lower than "recommended", but I always try to keep that differential pressure in mind.

I did the same with my 2009 Ninja; it came to me with "30 all around" and was very sluggish handling, requiring a great deal more handlebar pressure for banking than I thought it should.

Once I restored the 3 psi difference, everything perked up and she handles like she should. I guess K knows more about the fore-and-aft center of balance of my bike than I do.

Your mileage may differ.

Just a quick question for you, though. Are both tires on your bike the same in carcass construction? That is, are they the same manufacturer? Both radials or bias-ply?

Just a thought.

Thanks for the warm welcome!

[kkim]

Both tires are Bridgestone BT-090 tires, mounted brand new at the same time.

Like you, I've played/experimented with tire pressures both on the bikes and cars that I have owned. I value handling above all else in a vehicle's strengths.

Thanks for your input, but in this case, I highly doubt a difference of a few psi would cause the wobble problem I am experiencing in the front tire. For the record, I do have the pressures at 28f/30r at the moment.

Your car tires last you an entire year?? I'm lucky to get 8k miles out of a set.

[Alex]

Hi Michael!

Welcome. Asking kkim if he is sure he checked his tire pressure is like asking Rossi if he remembered to put on his leathers before taking to the track. He's posted up treatises on the handling differences between 28 PSI and 29 PSI in the front tire. (BTW, the book does say 28F/32R for the stock tires on the new-gen ninjette)

[kkim]

Originally Posted by Alex

Hi Michael!

Welcome. Asking kkim if he is sure he checked his tire pressure is like asking Rossi if he remembered to put on his leathers before taking to the track. He's posted up treatises on the handling differences between 28 PSI and 29 PSI in the front tire. (BTW, the book does say 28F/32R for the stock tires on the new-gen ninjette)

thanks... I think.

Hey... wait a minute... did you just call me anal??

[Alex]

uh, umm, well, uh...

[Verus Cidere]

Yup.

[mpdugas]

Well, I certainly mean no disrespect to KKim by commenting on the tire pressure thing. I actually was more focused on the fact that he was using the same pressure front and rear when K specifies a four psi differential ( I stand corrected on that, too; I was recalling from [faulty] memory the 3 psi difference which I first mentioned. I actually set mine to a four psi difference).

Too, that is an insignificant matter as well, since a properly-sorted ride may very well make good use of such settings as his.

I was thinking more of eliminating variables when trying to find a solution to this unhappy problem. As with working on a cranky PC or a car, default is the best place to start when trying to see what is causing a failure.

So when I troubleshoot, I try to find a stable starting point, introducing one new variable at a time. It's a PITA, but it works.

In fact, the pressure difference issue may be more important than first thought: KKim himself mentions that the wobble diminishes significantly when the bike has a load cantilevered out over the rear of the bike (I think he mentioned a rear-mounted luggage bag of 10 pounds).

That affects front-rear balance...and pressure differentials in the tires address the same thing.

In any case, I offer my suggestions only as a help, not as an affront...so hopefully, this will put matters aright.

[pedaltothemetal]

Originally Posted by mpdugas

KKim himself mentions that the wobble diminishes significantly when the bike has a load cantilevered out over the rear of the bike (I think he mentioned a rear-mounted luggage bag of 10 pounds).

If this is fact then can caused by the geometry change to the front!
Kelly you did move the forks up to lower the front or when you intalled your clipons? Put it back to stock height and see if the wobble goes away!

[kkim]

Michael,

I appreciate your input and value what anyone has to contribute from their points of view... it's how we all grow as a group... sharing different experiences we encounter as individuals. No offense taken from this side of the room. The wobble remains with or with out the bag loaded in the rear, adjusting tire pressures front and back, raising and lower the forks... almost everything I've been able to think of. (unfortunately just not the correct one)

The next step is changing out the front tire to see if that new tire I installed was the problem. I have the replacement ready and when I get off my lazy ass, I'll give that a shot.

Mahalo for all of your suggestions and feedback. This one really has me stumped.

[sofo]

Is the front wheel balanced / fork legs evenly adjusted? The former is likely a given, the latter makes me wonder if one fork leg is either sagging / dampening unevenly to the other.

[kkim]

I did my own front wheel balancing, using a method that has always worked for me in the past... on 600cc bikes that I rode at much higher speeds than I ever approach with the 250R, but it could be that it's unbalanced. I exhibit none of the other characteristics of an unbalanced wheel, though. No shaking or vibration from the front wheel at other than the decel situation from ~ 50-40mph.

The fork tubes both protrude above the triple clamp the same amounts.

[jlovaas]

Hi all-

Newbie poster here; I read this entire thread(!!!) this week. kkim, correct me if I'm wrong, but you've been living with this wobble condition since April of 2009! That's a long time.

sofo has the correct approach to this problem. There's a few(or maybe just one) item/s to check.

The matching distance of the fork tubes above the triple is no guarantee of alignment. Get the bike up on the center stand and remove the front axle- do you have to fight to get the axle in and out, or does it move freely?

It's super quick- check that front axle fit. The axle needs to be square to the fork sliders- if it isn't, something(fork tube, upper/lower triple issue) is out of alignment.

I have seen fork tube length tolerances vary by several millimeters on some very expensive import bikes. It all starts with some guy at a band saw, chopping up steel tubes. What's a +/- of a few millimeters to the machinist down the line? ;-)

If I've read your account accurately, the bike was fine before the tire change, and is bad now. All you had a mechanic do is remove the old tire and mount the new one, as I understand it.

Assuming the tire was truly a new tire, I've never seen an intermittent wobble caused by a tire- unless, I suppose, the bead isn't fully set all the way around- !!! And an error in balancing would be sensed at most speeds.

So what else changed? Brake caliper was removed/refit, and the axle was removed/refit.

Do yourself a favor- check that front axle fit. Addressing the wobble may save your hide someday.

If it was a fork oil/spring/steering head bearing issue, that would have existed before the tire change. New tires shouldn't make the bike less rideable ;-)

I know there are online tutorials, specific to the ex250, that can walk you through the process of "relaxing" the front end by loosening and tightening the upper and lower triples.

Looking forward to hearing the results of the experiment- jl

[kkim]

thanks, John. I'll check the forks for any axle binding.

welcome to ninjette.

[Momaru]

Results Kelly?

[kkim]

Sorry, I haven't been working on the ninja... been spending a lot of time on the dual sport lately.

[tltb26]

ALL,

My love is my first owned bike. She had her second "warrranty" service aprox. 4 weeks ago ($146-the service included oil/filter change to full synthetic, electrical inspection, tire inspection, fluid inspection/top off, general operational inspection). Since then, I noticed so far, three strange things. She has about 2000 miles on her and is a couple months shy of a year old.

1) I can FEEL the road through/with the tires (I can practically feel the grooves). The sound of the tires on the road is also more pronounced; I can hear it through my helmet & earbuds. It didn't seem so "loud" before. She FEELS MORE flickable (it actually scared me on accidental discovery, I repositioned my legs-ever so slightly- where I hug her and she flicked. I never noticed this sensitivity before; I had to actually intend & motion to lean or turn with the use of my legs. Is this what sticky is?

2) My tire pressure is now set at 32 psi Front & Rear. Yes, I'm aware of the manual recommendations and the max cold psi of 36 stated on the IRC tires. Maybe this is the cause of number 1? Does it matter that it is HOT/humid out here year round? In some people's opinions, we have poor roads (lots of potholes, roads/streets are either coral or asphalt, always construction & as with some other places inattentive drivers). I intend to drop the psi's by next week to see if there is a change.

3) I think, after acute observation for a couple weeks now, that I am experiencing a slight wobbling but more pronounced at over 40mph. Maybe the numbers 1 & 2 are the reason I'm feeling number 3? I do not remember this wobbling prior to the service.

I intend to observe her for another week and if the wobbling persists, I will take her back to the shop where they will charge me another limb.

Apologies if this does not belong here exactly...but I can attest to the slight wobbling. Thanks.

[randomwalk101]

Last week I was riding the ninjette and remembered this thread so I let go the bar at around 60mph to 35mph or so...abs no shake at all.
Posted via Mobile Device

[randobad]

Mine used to do this too.

I have since replaced the stock tires with Pirelli Sport Demons, put thicker oil (20 wt) in the shocks and set the oil height to 160mm instead of 205mm, replaced the springs with Race Tech springs at .70kg and aligned my forks by compressing the forks all the way before tightening the clamps.

Now it doesn't do it any more.

I'm thinking that realigning the forks with the caps off so you can compress them all the way, without the front wheel but with the axle in the forks, should do the trick. My fork tubes were also set 13mm above the top of the triple clamps.

Hope this helps

[CZroe]

Mine always goes away when I change the front tire even when it doesn't appear significantly worn and returns before too long after changing to it (on my third front; two were take-offs; all were GT501).

[randobad]

I forgot to mention that when my front tire was balanced, the tech put on a stick on weight instead of the type that clips on the side of the rim. Maybe all that is needed is to have the front tire rebalanced to kill the wobble.

[SCREEM]

I've had the problem since the get go, it's annoying for sure, but I trust my bike none the less.

[Samer]

If you do a search, you'll see a very long thread on front end wobbles. I wasn't sure whether to revive it or just start a new one, so I hope it's okay to start a new one since I'm just curious if anyone has recently experienced this particular situation:

I haven't had any front end wobble of any kind since I had my 09. I bought it new and it is 100% stock. I'm at 1900 miles and yesterday I experienced the wobble for the first time ever. I will check my tire pressure as that might be the simplest explanation, but I do check it fairly regularly, but not every day.

The symptoms I think are the typical of the 2008+ wobble, if there is such a thing. I decelerate with the handlebars free, it shakes at around 50 MPH. It is not enough to cause too much alarm. I can comfortably leave it that way and I don't feel like I'm losing stability.

I was very surprised when it happened because I specifically tested it when I was reading the older wobble thread and there was no wobble. Any thoughts?

[CZroe]

It goes away every time I change my tires and comes back for the last third of their usable lifetime.

[Samer]

Thanks. That certainly makes sense! Although I'm surprised that 1900 miles worth makes that much of a difference. I am in Florida and there aren't too many turns though

That is one of the only things I could think of that have actually changed. The slight wear in tire tread that is...

[austexjg]

I've noticed it happening on my '09 with IRC tires with 4059 miles.

[Alex]

No need to revisit it. Same problem / same thread.

/merged

[scotty]

My front end wobbles also. Always has, even when it was brand new. I wonder if it has something to do with the weight of the bike.?.? Mostly the front end weight.

I have noticed that when I installed my WoodCraft clp on's, it got a tad worse. It's not bad like, "OMG!! I'm gonna die" when i'm riding. Goes away the sec I put my hands back on the bars. Shakes happens for me between 40-60mph. I haven't tested it at a faster rate of speed though.

[Bueller999]

Originally Posted by scotty

My front end wobbles also. Always has, even when it was brand new. I wonder if it has something to do with the weight of the bike.?.? Mostly the front end weight.

I have noticed that when I installed my WoodCraft clp on's, it got a tad worse. It's not bad like, "OMG!! I'm gonna die" when i'm riding. Goes away the sec I put my hands back on the bars. Shakes happens for me between 40-60mph. I haven't tested it at a faster rate of speed though.

Change your tire. It has probably been said in this thread repeatedly but that is because that is more times than not the problem.

People buy steering dampers because they have handling problems, all that does is mask the issue, the problem still exists.

No it is not normal for this bike to wobble, wiggle, shake or shimmy. Not due to design or weight. If it is, it's a remediable situation.

Even tires that look like they have plenty of life left in them can cause severe handling problems.

[scotty]

Originally Posted by Bueller999

Change your tire. It has probably been said in this thread repeatedly but that is because that is more times than not the problem.

People buy steering dampers because they have handling problems, all that does is mask the issue, the problem still exists.

No it is not normal for this bike to wobble, wiggle, shake or shimmy. Not due to design or weight. If it is, it's a remediable situation.

Even tires that look like they have plenty of life left in them can cause severe handling problems.

I do have the OEM front tire on still. It does need to be replaced, it's all cracked up.

[Alex]

Originally Posted by Bueller999

No it is not normal for this bike to wobble, wiggle, shake or shimmy. Not due to design or weight. If it is, it's a remediable situation.

I agree with your point that adding a damper to deal with this is overkill and unnecessary, but your statement that this is a remediable situation in all cases is not supported by the experience of many. There is bike after bike after bike that has this behavior, and tracking down the primary cause in such a way that the problem is eliminated for good is often unsuccessful. Either individually, through a dealer, or through kawi themselves. Bar wobble on decel is a common trait on a number of bikes, including ours (and Gold Wings, and quite a few others).

On a bike that wasn't doing it that starts to do it as a tire wears, new tires do seem to often make the difference.

[BennyV]

I too have fairly bad head shakes, usually between 70kms/hr to 45km's hour. (Not sure in miles).

Recently had it in at the dealer for service and I mentioned it to them. The mechanic said that it's super common on 250r's to get it. They checked steering head bearing and front and rear wheel balance and alignment and found no anomalies.

Both myself and my brother have 2010 250r's, mine with 12K km's and his with 4K and both bikes do it, both completely stock (Short farkles).

The only thing that was mentioned was slightly uneven wear on my front tyre (Very marginally squared due to commuting), which could encourage the issue.

[cb160racer]

Kelly, did you ever resolve your wobble/shake? My '08 surprised me by all of a sudden doing it when it hadn't before, but I think I figured out why.

My situation: I was coming off a freeway ramp and coasting to a red light. I reached up with my left hand to open my visor but it was kinda stuck, so I reached up with my right hand, too. The instant I let go of the right handlebar I got an alarming headshake. It stopped immediately when I grabbed the bars again, although of course I was decelerating the whole time and by then I was only going maybe 20mph or so.

I hadn't ever noticed this behavior before, and I've ridden the Ninjette off the same ramp many times before. What was different is that I had a pile of gear on the back, and I had sat up and leaned back to try to get my visor open.

I'm about 5'10" and probably weigh like 165-170 with Aerostich, helmet, and boots. Compared to the bike, I'm a large dynamic load. Given the added weight on the back that day, when I shifted my own weight and added even more to the back, the front was too light and got headshake. I verified my theory by riding down the same ramp and letting go at the same speed but keeping myself leaning forward (hard on the abs and lower back at my age!). No headshake. Same thing again, but butt shifted to the very back of the seat and me leaning back: headshake. It felt exactly like my CBR600 coming over the top of turn 9 at Thunderhill, where the suspension unloads and the front tire often isn't touching pavement for a moment. A steering damper would likely resolve it, but I'll probably just be more aware of my weight distribution on the 250 from now on.

[kkim]

Craig,

no, I haven't resolved the wobbling. I still haven't changed the front tire yet, either... yeah, I know, I've been a baaaad boy.

my wobbles will occur if I have something loaded on the rear or not. I have not tried redistributing my weight front to back, so that's something I will need to try. Thanks for the idea.

What intrigues me about this wobbling problem is the fact that some have it and some don't. makes you kinda go.... hmmmmm.

[cb160racer]

Originally Posted by kkim

What intrigues me about this wobbling problem is the fact that some have it and some don't. makes you kinda go.... hmmmmm.

Yeah, and it REALLY surprised me that I hadn't had it before and then suddenly I did! But I think I've satisfied myself that it's due to F/R dynamic weight distribution, at least in my own case. Plus the Ninjette can hold nearly 30 pounds of fuel, which adds another variable to the mix.

[ratlab]

mine did the 45 mph decel wobble on the way home from dealer-the old honda 600's did it also-just a trait of some bikes-my bandit did it also-as long as it doesn't do it under accel your ok-my gsxr does it accelerating but the front wheel isn't on the ground

[kamikaze]

Mine's done it from day one, both on the old IRCs and my new BT-016s.

doesn't really bother me

[DaBlue1]

Has anyone noticed if the difference is in the type of weights and balancing machine/technique being used. I had the same wobble @ 45 mph, I noticed a difference with new tires and stick on weights. The stick on weights are mounted closer to the outside of the rim as the stock clip on weights are in the center of the rim. Auto tires also are balanced inside and out if necessary. This wobble at 40-50 mph is a phenomenon among other bike as well as cars. I believe it has to do with gyroscopic wheel stability.
This is an article that sheds a little lite on what we are feeling. http://www.cs.cmu.edu/afs/cs/project...r/gyrover.html