77 Wobble over 60mph?!?

[Grimly]

This happened to me at the 2018 VYR. My 12 Series Progressive Suspension shock had a weld fail at the top. Excuse the "me too", please.

Another "me too"; shortly after buying one of the GSs it broke down in London and I had to call a recovery truck. The truck bloke was tying the bike down and his strap pulled a shock clean off the top mount. "Hmm... what a &^%$" I thought. He shouldn't have been tying down to the shock anyway. Luckily for me he was a careless sod as the point of failure made itself known right then and not when I was riding it.
Turned out the rubber boot at the top of the shock had held road salt and moisture against the alloy shock body and it had been corroding slowly for years.
Just glad it didn't happen at 85mph.

 

[madmax-im]

At the VYR in 2019 one of my first rides on my newly acquired XS650..I had a wobble at 55 on a divided highway...Later I attributed the weave wobble to 2 things overly taut rear shocks and poor Dunlop tires..Front had enough tread but was cupped..the rear had uneven worn spots..some spots the tread looked ok and others it was not...In addition chain and sprockets were well past thier useful lifespan...Once new Shinko 712s went on and had the shocks preload dialed down and a new Xring chain with new sprockets and we have lost the wobble/weave thing...and I have more confidence in what the bike is doing in a curve at speed...

 

[XSLeo]

On rereading this thread A question came to me. When you were checking the steering neck bearings, you lifted the front wheel off the ground. At this point you turned the wheel left and right to feel for ease of turning as will as any roughness. When you lift the wheel this shifts the weight from the lower bearing to the upper. Even when properly adjusted, this shift can deaden the feel of the lower bearing.
With the bike setting with both wheels on the ground turn the wheel left to right. Does it still feel good.
While doing this lock the front brake and rock the bike front to rear. Pay close attention to see if there is any shifting of the forks in relation to the frame.
With the bike up on the service stand Try to shift the rear wheel left to right. This will indicate any play in the swing arm bushes. Any play here can effect handling.
On tires I learned along time ago that you set a cold pressure then ride the bike, or whatever at least 15 minutes at highway speeds. This warms the tires up to operating temp. This rise in temp increase the pressure. This increase should be 10% more than the cold pressure. If it's not up to the 10 % your cold pressure is to high. If over the 10% the cold pressure is low.
I've been setting pressures this way along time.
When I bought the Harley it was the first bike I got that had the owners manual. It said to set my cold pressures to 30 ft. and 35 rear. I did the checks and the pressure increase was right at the 10%.
On cars and trucks the tire pressure placard is very close. Most of them are for the stock size tire. Often the tires get changed out for some other size. This can change what the pressure should be. So you may need to adjust your cold pressure to compensate.
On a track bike I would set the pressure the same way. I would ride the bike at the speeds I would run on the track, not the highway speeds most vehicles should be set at.
With your tires pressure adjusted this way you maximize your tires performance. It's handling, braking and life expectancy.
Running tires to soft or too hard definitely effect handling. It also effect ride quality. Try experimenting with your pressures to find out yourself.
Leo