Wayne,
Sorry I did not see your post earlier.
The squeak you are hearing is coming from one or three areas of your suspension.
1) Any of the heim joint swivals (These should be greased once in awhile)
2) Any of the loose heim joint threads. (They will squeak as the ladder bar rotates slightly during any suspension movement).
3) Any of your shock mounting bolts. (This is where you would use the silicone spray).
Raise the rear end of your trike at least a foot off the ground. Support it on a couple of good sturdy jackstands.
You need to look closely at the heim joints. Here is what you are looking for:
1) Are the jam nuts tightly against the ladder bar ends?
If you can get your thumb nail or a business card between the jam nut and the end of the ladder bar it is not tight.
Using a wrench, if you can turn the jam nut with very little effort it has come loose or was never tightend correctly. If you can spin the nut just with you thumb and finger then there is a good chance loctite was never applied.
2) If you find the nut(s) to be loose, go ahead and back it away from the ladder bar end. Turn the jam nut all the way to the end of the joints threads to give you some room.
Using a very bright flashlight look at the threaded portion of the heim joint which threads into the ladder bar. Do you see any rust at the opening of the ladder bar end? Are there any threads on the heim joint with a dusty powder look to them? Look at the jam nuts themselves, do you see any rusty powder on the face that contacts the ladder bar or any dust cresting over the edge of the nut?
If you answer yes to any of these three questions, the nuts are loose. The ladder bar system integrity may have possibly become compromised.
If this becomes the case you will have to try to move the ladder bar up and down at the entrance of the joint into the ladder bar. You are now looking to see if the system is possibly worn out. You may have to have a compedant dealer check this portion out for you. The squeak will go away for a short time. But if you indeed have loose heim joint jam nuts you will have a bigger problem to deal with.
One other item I just thought about. Inspect the large bolts and nuts that mount the ladder bar to the rear end mounts. They have a habit of coming loose and moving with the pivot of the heim joint and squeaking while doing so. By the way, I replace all of the rear end mounting bolts and nuts on any Motor Trike conversion with nothing less than grade eight (8) hardware, and lots of loctite. Better to be safe that real sorry.
Mike