Not sure how it would apply (if it does) to double UJs as per Guzzi. Still see no harm in doing it anyway.
I am getting a thrumming sound from prop shaft, but does not sound destructive.
I will wait for the snow before I check as need to pull the swing arm to see rear joint. Good opportunity to lube pivots.
I too get the thrumming sound, with a very slight vibration, both increasing with speed. I have focused on the bevel box, being convinced that the play on the splines on the cush-plate are the cause. However, even a new cush-drive plate still has play against the female splines on the bevel box. I’m told that up to 2cm play (forward/backward rotation) on the back wheel is acceptable. I have come to the conclusion that perhaps my main drive shaft is not long enough (there is quite a gap between the rear end of the front UJ and the circlip on the drive shaft), and this allows the UJ to run out of whack. I could, of course, be completely wrong!
I thinking the thrumming may just be natural with two bearings mounted to the tunnel and maybe anti vibration pads stuck to tunnel side might dampen.
Are you sure your drive shaft is not too far to the rear. I will have a look at mine at the front as no idea how far it enters, just glad when it does!. They are predicting snow tonight in Calgary so may be a while, supposed to be back up to 18 by Friday.