Drive shaft twitch

[dubman1959]

Hi There,
My 52 Morry as every now and again started doing a very strange thing when idling, The drive shaft starts twitching and you can see the rear wheel stitching as well, very strange, and if you push the clutch in a little bit its all good , Any ideas, Cheers Steve.

[philthehill]

The only way that the drive shaft and wheel can twitch is if the drive from the engine via the clutch and gearbox is not fully disconnected.
You have proved this point by dipping the clutch & all is well.
You do not state whether the twitching occurs when the drive is engaged and the clutch is partially depressed & depressing the clutch further stops the twitching - if that is the case you have a dragging clutch - check the clutch adjustment.
The first motion shaft and the third motion shaft are engaged when in top and the shafts are disengaged when in neutral or in any other gear but 4th. It may be that the bearing in the rear of the first motion shaft and which supports the front of the third motion shaft is failing and picking up causing the drive shaft to twitch.
Can you please give further details.
Phil