Yamaha - Carburetor Bolt Set Carburetor Fastening Hardware 99999-04228-00. Overview. When you're working on carburetors, it's easy to overlook the hardware, but that's where a lot of problems can start. I've seen loose or mismatched bolts cause air leaks and uneven mounting that throws off engine performance. The Yamaha Carburetor Bolt Set 99999-04228-00 gives you the correct fasteners to secure everything the way it should be. It's a small detail, but getting the carb mounted right makes a big