Maybe you tore the diaphragm when you took the top off or the spring was already cut either way go back over the job. The spring looks the same on both ends. If it’s cut the double ring will only be on 1 side.
A stock spring has 2 rings on each end. If you cut yours and it has only 1 ring on 1 end to start with, it's way to short now. You will have to buy a new spring, then cut that. (Unadvisable, it's not a "mod" but some asshats idea of more throttle response) The gain is really nothing (throttle response), I did that too, and wished I didn't. I bought a new spring, put it in and have had no issues since then. Honda Stock, least trouble, and best reliability.