Clutch fully disengaging? Shift forks?
I doubt the clutch is the is the problem. Otherwise, you should be having problems with the other gear transitions also - not just 1st to 2nd.... the same clutch pack was reused. Could this be caused by a dragging clutch?
The shift rod linkage Pat Man is referring to is external and easy to access and adjust. However, if the problem is internal, then, yes, the engine will need to be removed and the cases split.Would you have pictures or diagrams I could look at. Is this something I can fix on my own or would I need someone to split the case?