The noise sounds typical of some wear/failure in the universal joints of your shaft drive or too much backlash in the crownwheel/ pinion (guess they have such an arrangement at the back wheel...?)
Current Project
1968 Norton P11A Desert Sled
Other bike (and daily ride)
2004 Yamaha FZR 600
Previous Bikes
78 Z1-R (resto)
91 Zephyr 750
73 Mach IV (Resto)
78 Z1-R
78 Z1-R (stolen)
76 Z900
76 Z650
73 Mach IV
72 Mach III
