A replacement float bowl drain plug for the Keihin carburetors on Honda CB350, CL350, SL350, CB360, CL360, CJ360, CB450, CL450, and CB500T motorcycles. This is the "big head" late-style plug that seals with an O-ring — a sealing O-ring is included with every plug. Sold individually; order two per bike (one per carburetor).
Replace the old and worn-out carburetor float bowl drain plugs on your Honda twins with a new set from Common Motor Collective. Our drain plugs are a direct replacement for the OEM plugs and are drilled through the body so you can drain fuel without completely removing them from the float bowl. Each plug is sold individually and includes a sealing O-ring.
Honda used two different float bowl drain plug designs across the production runs of these motorcycles. The early-style plug has a small head and seals with a flat aluminum washer. The late-style plug — what we sell here — has a larger-diameter head and seals with an O-ring.
This drain plug is hollow through the center and has four small cross-drilled holes in the sides. This design allows you to crack the plug loose and let fuel dribble out through the center hole without fully removing the plug from the float bowl. Over time, these tiny passages can become packed with dirt and sediment. When rebuilding your carburetors, clean these holes out with a piece of fine wire or a small drill bit to restore full drainage.
Clean the threads inside the float bowl. Apply a small drop of oil to both the new plug’s threads and the O-ring before threading the plug in by hand. Tighten with a flathead screwdriver — just snug, don’t overtighten.
No. This is the big-head plug that threads into the late-style float bowl. If your carburetor uses the small-head drain plug sealed with a flat aluminum washer, this plug will not be the correct fit.
Yes. Each drain plug includes one sealing O-ring. If you need additional O-rings (for example, during a full carburetor rebuild), our rebuild kits for the CB350, CB360, and CB450/CB500T also include replacement drain plug O-rings.
No. The plug is drilled through the center with four cross-holes in the body. Loosening the plug allows fuel to drain through these passages without fully removing the plug from the float bowl.
Last updated: March 2026
