I just put rubber grommets over the tube where it goes through the fan shroud on the front and back. You may have to enlarge the shroud holes a bit to fit - maybe not, if they're worn some, but they should fit snugly.
Once the grommets are on there, it doesn't move or rattle and everything stays put. Looks neat, too.
I also have a big throttle return spring over the cable between the fan shroud and the throttle linkage actuator lever, rather than return springs on the carb actuators. I like that better. My throttle cable is not angled hardly at all as it exits the shroud tube to run to the linkage actuator - just barely touches the tube at the top when throttle is closed and barely touches the tube at the bottom when the throttle is wide open.