Feedback from the Owner
Thank you all for suggestions and comments. A little history, and information on what I have found so far -
The builder (I am the second owner, purchased 2015, approx. 1290H hrs A&E, 540H hrs were accumulated by me) had the Antisplat front wheel bearing mod done. The front wheel has weights on it, so I am assuming, Allen balanced the tire at that time. It also has the AS Nose Job 1 (nose gear brace).
I replaced the front tire in 2017. I did not balance the tire, and I did not remove the existing weights. My thought being I would see if I noticed any vibrations during T&L. I did not. Sometime after that is when I noticed the airframe vibration, at around 140 k IAS. Unfortunately, I did not document when I first noticed it..... Scott's comment about the wheel spinning and being out of balance makes sense. I removed the weights (1 oz) last night and went for a quick flight. It was not the smoothest air, but it seems the vibration is gone or lessened.
My front wheel breakout is set at 25#. The wheel bearings are OK. I check this yearly. I also check for play in the nose gear leg/socket. I have not checked the tightness of the nose gear leg bolt since purchase. I will do that ASAP, and add it to the yearly inspection list.
The nose gear leg fairing has no pin & hinge in the fairing to hold it together on the back side. There is also no leg to lower cowl intersection fairing. The leg fairing is only held in place by the hose clamp near the wheel fork, and the tightness of the slot in the lower cowl that the fairing passes thru. I wondered if the leg fairing was vibrating, and this is what I felt.... It has been on my list to add the hinge and intersection fairing, per Vans RV7 DWG 45.
Next Steps:
Get the wheel balanced.
Take off the cowl and inspect the leg/motor mount socket and bolt.
Mount a GoPro on the wing tie down and get some video.
Thank you all, for your comments - greatly appreciated!