Clutch

I've got a problem with my clutch. I recently fitted a new 1776 with stage 1 clutch. Adjusted the cable (new a couple of thousand miles ago) and everything ran fine. Within 50 miles or so the clutch started to drag - difficult to find 2nd gear, crunched in to 1st and 2nd. I tightened the cable adjusting nut and everything was fine for another 50 miles and the same thing happened again. The cable guide tube is still firmly attached to the chassis. Any ideas?

I'd pull the cable out and check it for fraying and have a look
at the the flexable conduit they can rust and and fill up with
crap snaging the cable. refit with plenty of grease.