I have an '88 Venture Made in '87 with 35K miles. Not a Royal
I am getting a strong vibration at 3,000 to 4,000 rpm, strongest at 3,500.
I get this vibration in all gears including neutral with the bike not moving.
It does not mater if I am accelerating hard, steady speed or decelerating.
It is strictly engine rpm dependent.
Above or below that rpm and it is nice and smooth.
Any ideas of where to start looking?