How to rebuild the factory Keihin CV carburetors for the Honda CB450 / CL450 / CB500T

The Keihin CV carburetors found on the Honda CB450 and CL450 families of motorcycles are perhaps our favorite CV carburetors used on the motorcycles we support due to their ultra simplistic construction. They use a metal diaphragm, a clip style easy to remove bowl for jetting changes, and have very few brass components inside them. In our rebuild video we go over how to completely disassemble the carburetor to identify and inspect the components inside; It is important to familiarize yourself with the carburetor to know what parts in your carburetors can be reused and what pieces need to be replaced. 

Once torn apart and cleaned we go over how to reinstall the float bowl jetting and float needle and seat. We also detail how the method we use to accurately set the float height.

What is the carburetor float height for my Honda CB450 / CL450 / CB500T?

Once the carburetor float bowl is sealed up and completed, be sure to check your slide and diaphragm for anything that might bind it from freely moving up and down in the float body. These are the main components that allow the CV carburetor to adjust to your engine and throttle response. 

Once your carburetors are rebuilt, be sure to follow our CB450 / CL450 / CB500T Carburetor synching tutorial before attempting to start the motorcycle. 

How to Synchronize Carburetors The Honda CB450 / CL450 / CB500T

CB500T Carburetors: The carburetors used on the Honda CB500T are nearly identical in construction and rebuild process with the addition of a rubber anti-backfire diaphragm and vacuum sync port found on the carburetors. When buying a carburetor rebuild kit, be sure to purchase the CB500T version that includes the o-rings found in the anti-backfire mechanism. If the air cut-off valve diaphragm is in bad shape we offer those are optional add-ons on our carburetor rebuild kit listing.  

Update: We now sell a single universal CB450 / CL450 Carburetor rebuild kit that includes both the early and late style components. Be sure to use the correct pieces depending on which version of carburetors your motorcycle is running. 

Parts you might need: 

Carburetor Rebuild Kit

Carburetor Gasket And O-Ring Kit

Carburetor Float

Intake Manifolds