Some carburators and manifolds, like the Keihin PE24, require a rubber connector.
My manifolds were designed to fit a ShiftUp connector. Make sure you choose the right model for your setup!
201081-GP: Mikuni VM26
201083-GP: Keihin PE28, PWK21
201082-GP: Keihin PE22, PE24, CR Mini
I don’t always have this part in stock. You can also get it from Webike.