This part is a Starter Gear Cover and Starter Reduction Shaft. 
There is typical wear to the part as shown in the pictures. 
The item came off of a 1987 Honda ATC 250 SX. 
Item Manufacturer Part Number for the Cover is 11355-HA6-770. 
Item Manufacturer Part Number for the Shaft is 28130-HA0-770.
If you have any questions, please feel free to contact us. 
If our price is not competitive, please contact us, or make an offer! 
-Blue Collar Sales and Service

This Honda 11355-HA6-770 COVER, STARTING GEAR fits the following models and components:

Honda ATV 1987 ATC250SX A Left Crankcase Cover