Instability at high speeds

[argonsagas]

I did not see this mentioned, so, do you have a fairing of windshield of any kind on the bike?

Depending on model and design of these items higher speeds can lift the front a bit.

My 1100G had something similar when the front lifted slightly as wind got under the Vetter fairing.

Turned out time and the extra weight had considerably weakened the springs so when the fairing lifted the springs were doing almost nothing and it actually was almost floating.

A new pair of Progressive springs and fresh fork oil improved everything.


Also....check front-rear wheel alignment. This should always be a part of the checks when you install bearings, especially swing-arm bearings..

 

[Big T]

quick update i did put the stock suspension back on and although they are old and feel terrible for bump dampening as expected with 42 year old shocks, i did feel a bit more stable at higher speeds.

This points to an imbalance in the suspension, front vs back.
I suspect your shocks are too stiff and the forks are too soft

Better shocks and upgrading your fork springs should cure your issues

 

[bonanzadave]

Better shocks and upgrading your fork springs should cure your issues

I did that (progressive front and back) and tried multiple combinations of dampening and preload. Same.........

 

[wilsonsandy07]

UPDATE:

got about 4k of my own miles on the bike now, certainly ridable and i have pushed it about as far as itll go without further tuning/jetting carbs. it could feel more stable, but i can feel when the bike is fighting and back out when needed.

However, went on a longer run recently and was just checking some levels/psi and found my fork air pressure sitting at 30 PSI! not really sure how it happened since i serviced it to 7 like the manual says but it is what it is. dropped the pressure and it feels way better but i think my front tire is out of balance. im using balance beads and i couldnt notice it before as there was so much pressure on the front it was pushing the wheel down hard, but as i get up to highway speeds i can feel the vibration from the front tire and see it consistently jumping. its not coming off the ground but i can see it vibrating.

nice to finally put eyes on an issue

 

[alke46]

You might try eliminating the air assist forks. Don't really need the air if you have upgraded the springs and you are positive that the correct level of 10 wt. fork oil is used.

And while we're at it, what is holding you back from putting your bike info in your signature?