Quote Originally Posted by alanTDM
Chain might be knackered with some stiff links that will cause a jumping sensation as its not going round the gear box sprocket correctly so its jumping
Put the bike on the paddock stand and turn the wheel with the sprocket cover off ,if its stiff links you will see them.
I've had the sprocket cover off... nothing obvious in there and chain seems fine.

Could a loose sprocket cause the 'jumping'? It seems to be coming from the transmission, so it looks like I could be learning the hard way how to take an engine apart :'(