zed_thirteen wrote: If the screw heads are good enough to loosen them - then I would take them out and replace just the screws with Allen/socket head bolts. Much easier to tighten with a long ball headed Allen key
I agree with Zed_Thirteen here. Those clamps are specific to the 1300 carbs/ or throttle bodies. Allen head screws have a smaller diameter head than a standard philip head screw and will probably fit the clamp beter. The long ball driver would be the ticket for access and tightening.
It would be prudent to mention that the stock screws on most Japanese bikes are JIS standard screws. JIS is short for Japanese Industrial Standard which is one of the many forms of the Philip head screw. It would be in everyone's interest to invest in a set of JIS screwdrivers or screwdriver bits if you plan on working on these bikes. Best $20 you'll ever spend. JIS screws have a small dimple punched on the head of the screw to indicate the JIS standard See picture.