I agree with btb. Made the same mistake. That pesky woodruff key only goes in one way. I put it in the wrong way and had the clutch sticking out too far which produced the same result you describe. Easy to check. After removing the 132 screws that hold the outer case, sight down vertically on the primary chain - it should run parallel to the edge of the inner chaincase.
SORTED...Clutch not rubbing on case. After taking it all apart again and carefully checking all bits found that the new rollers I fitted to the clutch were 2mm longer than the old ones. put the old ones back in no noise.
