If you find that you have space behind your air filter housing after putting a spacer between it and your carburetor adapter, you either have the wrong conversion kit or a poorly manufactured conversion kit. This is a problem because it will allow unfiltered air into your carburetor. Don’t worry, though. You can eliminate this space by adding in a custom rubber or metal gasket. You’ll need to cut this to the same external size as the spacer, but with dimensions that plug the space behind the air filter housing.