Hey there everyone. I have a 2002 Kawasaki Bayou 300 4X4 Manuel that wont go into gear.

It has been sitting in a shed for the past 4 years, and I brought it out today to clean the carb out and get it running. After getting it to start and idle fine. its sitting in neutral . Upon getting on the Bike. It wont shift up or down to any Gear. and just remains in neutral. there is no click when moving to shift, only moves up slightly then stops. I tried rolling it into gear, but had no luck in getting it into first, or even reverse. It was working fine when I parked it in the shed back in 2013

What could be causing the issue? and how would I go about fixing it. any help is appriciated.