Could a slight increase in front tire pressure cause a slight vibration through out bike....... Or is something wrong here :? :? :? :? :? :? :? :? :? :? :? :? ...
(was running app. 31 psi and now 38psi)
You likely have some cupping/scalloping of the front tire from running them at 31 psi. You can see this scalloping if you look at the tire and compare it to these pictures. 8) http://www.rattlebars.com/valkfaq/tirewear/
If the tires have a lot of miles and are cupped, changing pressure could cause the vibration. That's what happened to mine this spring when I took it out for the first time. A new set of Metz 880's took care of that little problem.
Not the only fix... I rode all day long on a stretch of road we call Red Bluff Road, a old logging road, that follows a river.
My friend was on a Moto-Guzzi trying prove he could lose me. At the end of the day, no more cupping. I run 40psi front and back. 1800C
No problems since.