Stumped, wobble at medium-ish speed

[stickbow]

Hey all I'm completely stumped and frustrated at this point so I could use some wisdom. I've searched and tried everything I've found that addresses this. Basically when I'm going less that 40 or so I get a steady wobble in the front end. It gets worse when braking, but I don't think it's the rotors, its just the weight shift. This winter i pulled the bike down to the engine, and powdercoated frame, triples, and swingarm. I left the front wheel attached to the forks and just slipped them back in. Suspension is at stock settings, I've put a new rear on, checked that the swingarm shims were installed right, checked that rear wheel shims were all in the right spot. Forks are even in the triples, steering stem is torqued(installed roller bearings). Keeping in mind that this never happened last year I can only think that maybe I lowered the forks in the triples accidentally, so if anyone can give me the height above the triple on a 07 s2r or similar, or think of something else I can try it would be much appreciated.

Sincerely stumped
-Stickbow

[Howie]

Air pressure
Tire condition
Bent wheel
Wheel bearings worn
Head bearings improperly adjusted or installed wrong.

Also check rear wheel bearings and swing arm bushings.  It is sometimes difficult to tell which end is actually misbehaving. 

Any changes before and after like ride height, sag or preload?

[stickbow]

Hm,

Tried low and high
Same tires from last season, then replaced the rear, front doesn't look bad.
I doubt the wheels got bent just laying around all winter, would I be able to tell if I just spun them with the bike up?
Wheel bearings might be worn, but again would they change since last season?
Head bearings I had loose, then too tight, and now I think they are right. They turn easily but no up and down slop.
The settings were way weird when I got the bike, but I reset it to stock recently hoping it would fix the problem but no luck.

Thanks a ton for going over this, I'm going to try and check and see if I can see and tire wobble or anything.

It's hard to explain the feeling of what happens, but it feels like more of an alignment issue than bearing issue.

[SpikeC]

 Did you check the alignment of the rear wheel?

[Howie]

SSS, no new parts, wheel alignment should be correct assuming you shimmed as before. 

Hm,

Tried low and high
Same tires from last season, then replaced the rear, front doesn't look bad.
I doubt the wheels got bent just laying around all winter, would I be able to tell if I just spun them with the bike up?
Of course, best would be with a dial indicator, but you shoud see it if it enough to cause a problem. More than 2mm. is a problem.
Wheel bearings might be worn, but again would they change since last season? 
Probably not, but if water was in them, maybe
Head bearings I had loose, then too tight, and now I think they are right. They turn easily but no up and down slop.
The settings were way weird when I got the bike, but I reset it to stock recently hoping it would fix the problem but no luck.
Did you correct the settings before or after dis assembly for powder coating?  A good time line of events would be helpful

Thanks a ton for going over this, I'm going to try and check and see if I can see and tire wobble or anything.

It's hard to explain the feeling of what happens, but it feels like more of an alignment issue than bearing issue.

Fork height is 296+1mm. from bottom of lower triple to cap on the fork for an '06.  I think an '07 would be the same.  This assumes stosk forks.

[stickbow]

I think that might be it, but you mean the very top of the forks, where you adjust them? Or the top of the tubes?

[stickbow]

Ok I found it in the manual, but I'm confused, if I measure it that way I can never get it that high, 296, and to get it longer I have to drop the triples, which isn't how the picture looks in the manual. I think my are much too low, and I need to jack it up to stabilize the steering

[Howie]

Do you know exactly what forks you have?  Stock?  Are the triples stock?  Maybe a good photo of the forks and triples?

[stickbow]

Ok I just jacked up the triples to how it looks in the manual pic which I think is correct, basically they can only get 5mm higher before the forks drop out of the triples, but a quick test ride says it definitely didn't fix the issue.

[stopintime]

No expert, but since it goes away over 40 - I'm thinking that a wheel, or two, goes from wobbling to straight. You'd probably know if that was it, but anyway, are you sure the wheels are mounted correctly? Spacers a.s.o.?

[stickbow]

Im far from an expert, brainstorming is much appreciated. the front hasn't changed since last season, I jut slipped the forks back into the triples. I just hoisted it up and looked for any runout and didn't see anything, though I'm not sure if by eye is good enough. The rear I checked before, then remounted the rear tire. According to the manual I have the shims in the right spot. Plus when I use the string technique to align the two they look like they are on the same line. Does anyone have any other methods to checking alignment?

Also I think at quicker speeds the gryo effect of the tires is what's correcting it, and it is definitely worse when I roll off the throttle hard or brake

[stopintime]

Next brain storm item: when front wheels are put back on, I've seen mechanics push down hard on the handle bars a couple of times to make sure the axle is straight through the fork bottoms... Maybe your axle/fork got a little twisted along the way...  Not the most obvious suspect, but very easy to try - loosen the axle bolts and push before tightening again.

[Speeddog]

Did you make sure to get the rear wheel back on correctly, pins in the holes, not the slots?

'Cause it'll tighten up ok, but then get loose when you ride, as it's just sitting on the shoulders of the pins.

Gap like this:



Wheel ravaged like this:

[brad black]

What tyre pressures are you running?

[stickbow]

Thought maybe I had screwed up the wheel like that but no dice, fitted properly.

Psi is 36/34 or so.

Is it possible to have the front wheel off center if I never disassembled the axle? Should I try that bounce technique with the front and retorque the axle nut?