Honda Motorcycle CBR600F F4I Turn Signal Bulb Size
Honda Motorcycle CBR600F F4I front turn signal bulbs measure 1034 in size, while rear turn signal bulbs measure P21W in size. The replacement chart covers 2001 to 2006 model years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Honda Motorcycle CBR600F F4I uses two distinct bulb types across its turn signal positions: the 1034 for the front and the P21W for the rear, a split that holds across the full 2001-2006 model range.
The 1034 is an ANSI-standard bulb, meaning it conforms to North American specifications used in the United States and Canada, and operates at 12V with a dual-filament configuration rated at 21/5W.
The dual-filament design of the 1034 allows a single bulb to serve two brightness levels, with the higher-output filament typically handling the turn signal function and the lower-output filament handling a secondary role such as a running or parking light.
The 1034 uses a BAY15d bayonet base, which is an offset two-pin base. The offset pin placement is a physical keying feature that prevents incorrect insertion of a single-filament bulb into a dual-filament socket.
The 1034 is a variant of the widely available 1157 bulb. While the two share the same BAY15d base and general construction, they differ in voltage or wattage ratings, meaning they are not directly interchangeable without verifying the specific electrical values.
The P21W is an ECE-standard bulb, conforming to European and international regulations, and operates at 12V with a single filament rated at 21W.
The P21W uses a BA15s bayonet base, which is a single-pin base. Because the BA15s base differs structurally from the BAY15d base of the 1034, the front and rear turn signal sockets of the CBR600F F4I are not interchangeable with each other.
The P21W single-filament construction means the rear turn signal socket on the CBR600F F4I is wired for one function only, unlike the front socket, which accommodates the dual-filament 1034.
Both the 1034 and P21W share a nominal operating voltage of 12V and a full-brightness output of 21W, making their light output comparable at peak operation despite their differing standards of origin and base types.
The consistent bulb specifications across all six model years indicate that no changes were made to the turn signal lighting configuration of the Honda Motorcycle CBR600F F4I between 2001 and 2006.