How do you put a vacuum on a Honda ac?

A Honda AC unit is no different than other automakers units. You put an "Evacuation Pump" on the system and pull it down. A cheap pump will run you about $100.00 (US Dollars) and a good one will be upwards of $500.00. A search on google will provide you links, but it maybe cheaper to have a local shop do it for you (can charge the system as well).