76 kz750 choke question

Just picked up a 76 kz750b1. Carbs were off it and had already been rebuilt. After putting carbs back on the bike I discovered that there is nothing to hold the choke lever in the closed position. You can lift the lever to choke the bike but it just falls down when you let go. I assume there should be a spring or catch to hold it but I don't see any obvious place where it would go. Thanks in advance!

There should be a screw, spring, and 2 washers that apply pressure to the little choke lever. The screw can be adjusted to make the lever tighter or looser depending on how much pressure it applies to the spring. The diagram below shows the parts for the KZ750-B1. Below that are 2 pics of the choke lever on the KZ650-C1. The carbs are different than yours, but it should give the general idea. Ed

Thanks! I will try tightening that up later today.