Motorcycle Questions? Ask a Mechanic.
You likely have an out of adjustment, worn, or damaged shifter mechanism. The only adjustment is of the centering of the shifter pawl. I can help you with that if you would like to try it yourself. Anything beyond that will require some in-depth disassembly and measuring to determine the issue.
I hope this helps. Please let me know if I can be of further assistance. Also, please leave a positive rating for my service today. Thanks, P.J.