31-08-2019, 11:01 AM
(This post was last modified: 31-08-2019, 11:04 AM by Tony Griffiths.)
If you replace the rear bearing the rumble will, for a while, disappear - so that's its source. However, goodness knows what sympathetic and interacting vibrations are set up as a consequence of a "loose" main and so amplify the noise/vibration/harshness at various combinations of revs and ignition advance.