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View Full Version : Steering Shake Help Needed



MotoMan
01-30-2005, 05:26 PM
Here's the skinny.

1) I dropped my bike trying to load it into the truck for the move from Dallas to LA.
2) Resulted in cosmetic damage, handle bars, etc., but most importantly twisted (didn't bend) the front forks.
3) I straightened everything out and it rode just fine.
4) Got my new tires put on yesterday and now I'm getting head shake.

I'm thinking maybe the front end isn't as straight as I thought it was and with the new tires everything is being magnified. Or maybe I've bent something on the front end that's causing the shake. I understand that a shake is inherent in sportbikes because of their steep rake angles, but this is a Ninja 500 and I don't think the rake is all that steep. Now I did also put on clip-ons recently, but I'm not sure how that would affect anything because I put very little weight on the bars.

Does anyone have any ideas? I apologize if this should go into a different section, but I wanted to make sure as many people as possible saw it. I'm sure this isn't the first time a problem like this has come up.

Thanks in advance folks!

ezblast
01-30-2005, 05:50 PM
Are the tires balanced on the wheels?

MotoMan
01-30-2005, 06:07 PM
They should be. I just got the tires installed yesterday and watched the guy balance them. From what I could tell they were balanced perfectly.

Another thing I just thought of. I noticed that it doesn't shake all the time. Sometimes everything seems perfectly smooth, but then others I feel the shake. The shake doesn't seem to be dangerous (hopefully not), but more irritating than anything. I've never felt not in control because of it.

LoDownSinner
01-30-2005, 06:14 PM
Check out this article:
http://www.custombike.org/tech_forks.htm

Galaxieman
01-31-2005, 12:33 AM
If the fork tubes aren't bent, they'll pretty much self-align if you only loosen one triple tree (upper or lower) at a time. Get the front end off the ground, then loosen one of the trees. If that tree is tweaked at all, it should pop back into alignment when you let the 'grip' on the fork tubes go. Tighten it back down, then loosen the other tree. Again, it should pop straight if one of the fork tubes is torqued crooked. Re-tighten and repeat if necessary (or if you're anal/paranoid like I am).

Given your description of the drop, I wouldn't think it should be the steering head bearings, but if it was used when you got it, I definetly recommend lubing those bearings really good, as the previous owner and the shop you got it from shouldn't be trusted to have done it. Out of sight, out of mind, it must be ok since the bike turns fine...

-Jim

MotoMan
01-31-2005, 01:59 AM
Galaxieman, I can't imagine it would be the bearings either since it's an '04 and only has about 5,500 miles on it.

I didn't realize there were two trees you could loosen. I loosened the bottom tree and then tried to straighten everything by putting the front wheel between my legs and twisting the handle bars. It seemed to work pretty well, but maybe there's a little bit left to do.

Also, since I didn't have this problem with the old tires, I'm curious as to why it would just now be showing up with the new tires. But then that leads me to ask the question of how the front end might have adjusted itself when I got the new tires put on since it was off the ground and the front wheel removed. Maybe I didn't have something right and this caused something to get out of whack.

After I read the posts above, today after my ride I messed with the forks again (not the top tree, just the bottom), and I seem to have straightened it out a bit more. The shake seems to start at around 50 mph. If I let go of the bars, put as little pressure on the throttle as necessary to keep my speed steady, the bars oscillate back and forth probably 1/8 to 1/4 of an inch. Probably closer to 1/8. If I put both hands on the bars the shake pretty much goes away. I can feel it only slightly. I got on the highway as well and got up to an indicated 80 mph (I was just keeping up with LA traffic) and I noticed some shake, but it wasn't as bad as before I last messed with the forks.

I'm baffled. Can you tell me how to loosen the top tree on a Ninja 500? I don't have my maintenance book with me. I think that's my next thing to try. If that doesn't work I think I'll just take it in and see if they can find anything wrong with it. Like I said, I didn't notice the shake with the old tires, so I'm really baffled.

Thanks for your help everyone.

MotoMan
01-31-2005, 02:21 AM
Actually, I just went to ronayers.com and found a schematic of the front end, so I think I know where I need to loosen. Unfortunately I probably won't be able to do it until this weekend, but then I guess that will give me some time to plan a course of action.

Could the front axle be bent? Would the mechanic have noticed a bent axle when changing the front tire? Is there something the mechanic could have failed to re-install when he put the front wheel back on that would cause a shake?

Man, I hate it when I have a problem like this. I can't stop thinking about it until I find a solution. Maybe I could call in sick this week. :-)

Warlock
01-31-2005, 06:37 AM
You might want to recheck the alignment. On my bike there is a procedure you have to follow to align the front end back up after installing a new tire. Also just because they are new tires they can be out of round. Pick the front end up just enough so the tire doesn't touch. Try rolling the wheel and see if it touches anywhere. Like I said could be a bad tire.
Warlock

ezblast
01-31-2005, 11:35 AM
Concur - or the weights may have fallen off - lol

El Guapo
01-31-2005, 12:03 PM
I'm guessing it is your new tires. Maybe he didn't balance them perfectly after all or something. He did balance it with the brake rotor on the wheel, right?

FWIW I get an odd head shake on my Ninja 500, also. But mine only happens at kinda low speeds (approx. 30 mph or so) but at highway speeds when I let go of the bars the shake doesn't happen. Only when it slows down does it start getting squirrely, but I think my front rotor might be warped, though. I was planning on getting a floating rotor soon to try to prevent it from happening again.

MotoMan
01-31-2005, 01:33 PM
I called the shop this morning and talked to the service supervisor. He was very helpful. He said that it's doubtful an alignment issue as shake is usually caused by something being either off balance or bent. So hopefully tonight I'll get to check the front wheel to make sure it's not bent. I'll also check for tire roundness as Warlock suggested.

One other thing that I forgot to mention, but that I briefly thought of last night on my final test ride, is that the Pirelli Sport Demons have a sine wave groove along the middle of the front tire. Here's a picture of it on the Pirelli website.

http://www.pirellimoto.com/en_96/tires/template_categorie.jhtml?selected=desc&catid=96STXPL&productid=16927&nome=SPORT_DEMON

I wonder if that has anything to do with it? The service manager is going to call Pirelli and ask them about the recommended tire pressure and also if they have had any problems with shake. I've not seen it mentioned for the EX500, but maybe if my tire pressure is wrong that could be the culprit. Perhaps if the tire is over-inflated (it's set at 32 lbs right now, per the owner's manual, but maybe that's not the correct pressure for this tire on this bike with this rider), so much pressure is being placed on the sine wave groove that maybe the front wheel is basically just tracking along that groove. I've heard that improper tire pressure can cause the shakes in some cases, so maybe that's it. Just another thing to check out. The old tires had a center groove as well, but it was straight. Also, the service manager mentioned that this tire probably has more of a rounded nature to it than the stock tires, so there is less contact patch in the middle, but more on the sides. I would agree with that, as I've notice cross winds make me move a lot more on the new tires than on the old. So that could be an issue as well. So maybe the tire pressure needs to be a little less than standard to put more of the rubber on the road and get the pressure off of that sine wave.

I hope to find out more today. I told the guy that I will try everything I can this week so as not to have to bring it back in. I'd rather be riding the twisties this weekend versus sitting in a shop to find an elusive problem.

I really appreciate everyone's help with this. I'm really glad that I've decided to do as much of my own maintenance as possible because I'm really learning a lot about how a bike works. It's good stuff.

Thanks again.

banner
01-31-2005, 04:53 PM
You could be onto something with the tire pressure issue. I had a head shake on my F650 earlier this summer that was due to low air pressure. It was only a problem at higher speeds (65+). Once I re-filled the tires the issue went away completely.

ezblast
01-31-2005, 11:52 PM
Naw - only thing the lower pressure will do on a new tire is wear the center faster - if you don't do twisties often for the sides - lol - Pirelli's are the stickiest out there - maybe they need rebalancing - strange though if all the alignment and balancing is right - perhaps the release agent that new tires have as a coating is thick in a small section of tire - causing your problem - a thought...

MotoMan
02-01-2005, 01:24 AM
Well, the guy at the shop spoke to a Pirelli rep. They haven't had any problems with the Sport Demons and shake/wobble. The only difference is that the rep said they recommend 34 lbs in the front, 36 in the rear. I'm not that far off, so I can't imagine the pressure would make that much difference.

The next thing is to check out the rear wheel alignment, double check the front again, and if that doesn't help, them I'm takin' her in to have it rebalanced, replaced, whatever. It just doesn't seem right. Well, since it's wobblin', I guess it isn't right. :-)

Thanks for everyone's replies. It's amazing what you can learn on this board.

MotoMan
02-03-2005, 04:28 AM
I just wanted to update everyone on my wobble and shake issue.

A guy on an EX500 board mentioned that almost all, if not all wobble issues with bikes is caused by misalignment of the wheels relative to each other. In my case the back wheel was out of whack. Basically when the wheels aren't aligned properly they both want to travel in different directions, so they are fighting against each other. One of them wins at some point, and pulls the other where it wants it to go, which basically translates into a mini-skid of the tire across the pavement as it slides back into the "proper" plane of travel. This happens several times a second, which is noticeable as a wobble.

So I took this guy's advice and checked out my rear alignment. After messing with it for probably 3 hours, I think I finally got it. I used the string method, which was a real pain in the bootay because I was using the lights in a parking lot and the headlights of my car for light. Damn hard to see in the dark. I used bright green masonry line, so that helped some.

Here's the deal. I think the guy at the shop got it wrong, but after aligning it myself I can honestly say that I don't blame him. For those of you that have never done this, here's what's up with the EX500. The manual says to line up these little notches on the sleeves or whatever the hell they are on the swing arm. Well, that would be easy enough except that the sleeves move independent of the axle. So you could have the notches lined up, but the axle could be about a 1/16 to 1/8 of an inch (or more) out of whack because of the play relative to the sleeve.

After messing with the string method forever and constantly screwing it up because of the sleeve moving and everything else moving when I tried to tighten down the axel, I said screw it.

So what I did was loosen everything up, sat behind the rear wheel, spun it (slowly and quickly) while looking at the chain on the rear sprocket, and made sure the sprocket was hitting the middle of the chain. Then when it was time to tighten everything down, I pushed both of the sleeves that are on the swing arm as far forward as possible so there wouldn't be any play in them. Then I looked at where the notches were relative to each other. And lo and behold they were right on the money. Maybe only off by a fraction, but that was good enough for me.

So I got everything tightened down, cotter pinned, adjusted, whatever, and took her for a test ride. No more wobble. Well, there is still a slight wobble between 45-50, but that's it. No wobble below that, no wobble above that. If I get up to about 50 and then let off the gas and let go of the handle bars, sometimes I could initiate the start of a pretty good head shake, but it didn't happen all the time and when I grabbed hold of the bars again it disappeared instantly.

Alright, so this is a long story, but the gist of it is that it was the alignment of the rear wheel all along. And the moral to this story is don't trust the notches on the sleeves on the swing arm on the EX500. Actually, the only way I would is if you make sure they are pushed as far forward as possible to eliminate any play in their movement before you try and match up the notches and before you tighten everything down. Based on what happened with me tonight the readings are then pretty accurate.

Also, I made one final adjustment to try and get the handle bars as straight as possible after I finished everything else up. I loosened both triple clamps Galaxieman. I think I finally got it right this time. I didn't test ride it after that, but hopefully that little tweak will get rid of the 45-50 mph wobble. If so, then I'm in business and I'm hittin' the twisties this weekend. Actually, even if the small wobble doesn't go away, I'll be happy with it because it's not bad and it's just that 5 mph gap. Everything else feels great.

Rock-n-roll baby! Thanks everyone for your help with this. I know I learned something from this whole ordeal, and maybe someone else can learn from me.

Thanks again everyone!

Warlock
02-03-2005, 08:36 AM
On the Valkyrie there is a slight wobble between 30-35. Gets worst as the tire wears. I run 42 lbs in it,of course this is a heavy bike. Getting ready to change out my front tire. I will remove the wheel myself and carry it to have the tire replace and install it back on the bike myself. Got a lot of manitenance to do on mine getting ready for a iron butt run. I'm glad you got it to act better. For some reason a lot of bikes will have a low speed wobble, something to do with the rake. I would rather have it low speed instead of high speed.
Warlock