Gear problem on ar5516

If the shifter moves freely when engine is off. Its possible that the clutch is not fully dis-engaging causing stiff gear changes. May be time for a clutch

Underneath the stick, there might be a problem like a stuckup or broken plastic shifting bearing. Check this one.

main motor gear broken,please change it

check the shifter mechanism for binding up and not moving freely into positions. Not starting in park but in neutral indicates something is out of alignment with the shifter. May just need cleaning and a bit of oil/grease to fix.

Are you sure you installed clutch plate facing right way? They are either stamped or have a tag says "flywheel side". Or might have wrong clutch kit.

have you checked that the accelerator cable is moving freely, or that the carb slide is moving freely?

try to check the developing unit gears & check the toner cartridge maybe not insert properly or the sticker seal is not removed

check the linkages from the stick to the gearbox,

This is most ofthe related to lubrication of the cable, end bushings, and linkage at the tranny... especially at this age

You may want to disconnect the cable underhood and see if the floor shifter is mroe comfortable...

If the stiffness remains, I would suggest replacing the cable (lubrication is possible, but messy with the cable installed in the vehicle)

If your shifter move VERY freely, then likley the end bushing or linkage at the tranny - simple "maintenance" cleaning and lubrication should get you there.

IF the shifter at the tranny does NOT improve with external ceaning and lube, you may wish to flush/change your tranny fluid - many people do not perform regular changes and the position of the shifting bell-crank on the honda will allow dirt to accumulate and that shaft will bind as it passes through into the tranny.