[Honda Mechanic]

Sounds like your going to have to remove the alternator cover and check the shifting assy ..

If you need any PDF shop manual sections just post or PM your email address ...

 

[Honda Mechanic]

There is a stopper arm (with a roller on the end) this rolls around the shift drum center holding it into each gear .. Sounds like it could be bad ..

there is also a centering pin/post that centers the shift shaft , we used to have trouble with it coming loose and/or breaking so you should check all the shifting assy while the cover is off ..

 

[Honda Mechanic]

To check the gearshift assy you don't have to pull the flywheel ..

 

[Honda Mechanic]

Yes to split the crankcases to work on the transmission you have to pull the motor , remove the top end , remove the clutches & flywheel ..