My speed wobble occurs around 74-77 mph. The only thing that solves it is getting off the throttle, which I find odd.

The bike never did this before I got my 120/70/17 front avon and my 130/80/17 rear. I'm thinking the rear is too tall or my front tire isn't balanced correctly.

This morning I was doing a long freeway ride with my grandfather-in-law, and I found out that if I lean back and open my legs away from my tank, I get 0 speed wobble even up to 80mph. If I am going 80mph and I close my legs back to my tank, it wobbles like a ****.

Anyone have any experience with this sort of thing?

 

Tire pressures?
Wheel balancing?

That's an unusual combo: 130 & 120.

I did a spoke check on my bike about 6 months ago (1st time in two years btw) & many of them front & rear were loose!

 

If your rear tire is larger diameter, it is tilting the bike up in the rear, causing the steering tube to pick up a steeper angle. To get the angle back to stock, you'll need to drop the tubes in the triple, thereby reducing the angle.

 

My spokes are all tight, I just put some sexy spoke wraps on them , and they were all up to tightness.

I was thinking as well the rear is jacking up the front too much, a 130/80 compared to the original 130/70 is about a 13% difference in height. I'm due for new tires soon, so I'll just deal with it until then. 150/60/17 is closest to stock height with increased width..

130r 120f is a sucky combo, my front is constantly wanting more lean angle in the turns while my rear has 0 chicken strips, and even washing out a few times due to smaller width

 

Preload forks abit more

 

+1 Preload forks abit more.

I had to experiment with washers after I fitted my new harder springs, as I had a slight speed wobble.

5 pre-load washers in each fork (just less than 0.5inch thick) stainless steel from hardware shop, stopped the wobble in it's tracks!

 

What is your suspension sag since the preload install?
Basically you raised the front end the same dimension as the increase in tire radius.

 

had an avon on a zx-9 cause speed wobble at 120mph every time like clock-work. Tried balancing, suspension setting, everything I could think of to remedy it. Finally wore it out and bought a different tire; no more speed wobble.