Picked up a barnfind 1973 CB450 that sat for many years in a barn. The shifter can physically move down, but has zero give when trying to push it back up into neutral. I got the bike running, and drove it around the yard in first, and the clutch free'd up, so now it's easier to move. What might this problem be, and are there any good threads/ videos on fixing it? I'm thinking a bent shift fork but I figured I'd let some other people weigh in. Engine sounded healthy otherwise. Thanks.