If storing the bike for winter, use the drain screw at the bottom of the bowl to empty the fuel.
While a full rebuild kit is the gold standard, many riders look for "patches" to get back on the road quickly. mikuni bs25 carburetor diagram patched
Based on typical BS-series CV carburetor diagrams, these are the primary parts you will find: Upper Section (Vacuum Chamber): Top Cover: If storing the bike for winter, use the