Speed Wobbles

[parox91]

So my problem is speed wobbles and I suspect it's this:
-I'm missing ~3 bolts from the faring, (one of the bolts had to be drilled into to break it from the faring cause the PO decided to cross thread it pretty good)
->Any good cheap bolt kits I can invest in?

I just rode my gf's bike and she could handle all the way up to 100mph+ just fine but she has a lower aftermarket suspension from the PO.

[Alex]

/moved to pre-gen tech

[parox91]

Originally Posted by Alex

/moved to pre-gen tech

Derp, thanks.

[Motofool]

Originally Posted by parox91

......
-My suspension has been raised to the max seat height by the PO.

Which of these could be contributing to speed wobbles past ~92mph?..........

How did the PO achieved that?

Slow down !!!

[parox91]

Originally Posted by Motofool

How did the PO achieved that?

Nvm, it wasn't adjusted.

Originally Posted by Motofool

Slow down !!!

I'm just keeping up with the flow of traffic (and then a smidgen)

[FvnnyL3tt3r1ng]

I've had head shake for months now I suspect it's the stem bearings needing to be replaced or at least adjusted. There is an upgrade to that for ~$40 from allballs.com <-- I think that's the web address....

[Motofool]

Originally Posted by parox91

Nvm, it wasn't adjusted.

I asked because the pre-gen is not adjustable and wanted to know what he had done and how high the rear was.

The front being lower than the rear makes the steering more sensitive and less self-correcting, which in my opinion avoids steering oscillations, but until certain point.
If too much of a difference, then it can becomes dangerous unstable.

In summary, if your height difference is moderate, the cause of your the problem may be a loose steering column (bearings), telescopic tubes with excessive play, swingarm pivot with worn shaft or needle bearings, a poorly lubricated chain (with hard kinks), ........ but the main culprit frequently is the absence of handlebar weights (those dark cylinders in both ends) or a big heavy tail trunk.

[choneofakind]

Absence of bar weights doesn't cause headshake.

It causes buzzy grips. Same idea, different scale.


I've been without bar-end weights for somewhere around 8000-10,000 miles now. No tendencies to headhake caused by that. Now raising the tail definitely made it lighter and more sensitive to hand inputs when the front gets light over crests or bumps, but still no shake that wasn't caused by me

[parox91]

So I was talking about it with a coworker and he concluded that since my gf's bike is lower(Aftermarket parts), there's less weight on the front for it to induce speed wobbles. That and, I'm about 30lbs heavier than her.

Therefore, last night I decided to do a test as I was following my gf @ 95mph, I sat my butt further back and decided to tuck in but not putting any weight on bars/tank, and mostly on seat/pegs...


I didn't wobble but it felt as if I was going to fly off the bike if there was a headwind

[parox91]

Originally Posted by Motofool

I asked because the pre-gen is not adjustable and wanted to know what he had done and how high the rear was.

The front being lower than the rear makes the steering more sensitive and less self-correcting, which in my opinion avoids steering oscillations, but until certain point.
If too much of a difference, then it can becomes dangerous unstable.

In summary, if your height difference is moderate, the cause of your the problem may be a loose steering column (bearings), telescopic tubes with excessive play, swingarm pivot with worn shaft or needle bearings, a poorly lubricated chain (with hard kinks), ........ but the main culprit frequently is the absence of handlebar weights (those dark cylinders in both ends) or a big heavy tail trunk.

So there isn't a magic nut/spring I can loosen to adjust the seat height?

The suspension may have been altered, I really don't have a stock ninja to compare it with; I'll put pics up this weekend of the two bikes and a reference point with measurements of the sag.

I'd do it sooner but school/work has left me with no time to myself

[agentbad]

I only get it when I take my hands off the bars.

[Motofool]

Originally Posted by parox91

So there isn't a magic nut/spring I can loosen to adjust the seat height?

The suspension may have been altered, I really don't have a stock ninja to compare it with.........

No, the pregens have not adjustability for that, unless the OP had replaced the original shock absorber by one that was adjustable.

Correcting that steering oscillation may take some time because you will need to change things and test the results.

These are some measurements of my stock pre-gen: