96 RM80 Won't go into neutral or first

Trans will not shift into first or neutral. I have the clutch cover and clutch off but can't initially find anything wrong with the external shift mechanism. Is there anything I could be missing or do I need to split the crankcase to get to the trans to find the problem?

Any ideas on how to split the crankcase halves without the special tool the manual says to use?

Thanks
D7Cook@aol.com