I have finally tracked down a loud clonking noise when selecting forward after being used in reverse. I thought it was sort of headstock noise, but finally tracked it down to the undermount single phase motor. This motor is mounted on rubber mounts at each end of the motor frame. Over time, the rubber has worn / lost its elasticity allowing the motor to rotate some 60 degrees or so when it is reversed. In spite of doing up the clamps which pinch the rubber mounts onto the motor it still rotated in its mounts.
In desperation, I fitted a stay between the motor case and the motor platform which is raised and lowered to take the tension off the "V" belt (Motor to cross shaft).
Whilst in maintenance mode I took a link out of the headstock belt which begs the question, which direction should the segmented belt run in normal forward operation.
Forgot to add – its a Nu-T-Link type belt
BobH

Edited By Speedy Builder5 on 05/11/2015 21:14:07