Someone in the past on one of these forums said he loved his AC 500 but it had more rattles than a Jamacian Band. Thought that was pretty funny, still do. I have picked up a very loud vibration when down shifting at the same rpm range irrelavent to gear. After close inspection it is coming from the plastic skid plate, toward the back about a foot from the end. There is not much holding it there and I can move it up and down against the frame.

Well here is the question. I thought I would use some heavy duty wrap ties one on each side to secure after drilling a small hole. Does this sound resonable or has someone else found a better solution?

as long as that hole goes in the skid plate and not the frame, hehe.....sounds good to me.
i have a few "zip" screws in the plastic under the tank on both side where the plastic kinda clips together. stop the noise any way you can without compromising the integrity of the frame.

The screws on the skidplate will not tighten down any further??

The screws are tight the material is bulged up just a little and it is enough to vibrate. I used the wrap ties, one on each side and it tighten up the bulge with a slight indent were the tie is, so I think the objects will not get at the wrap ties. Will see how long this lasts. The skid plate material seems a litttle bunched up in places but maybe it is needed for colder temperatures.

I had a aluminum skid plate, full length, on a Rancher. It was rock solid when installed, and offered great protection. The only negative I noticed was it amplified any thing that hit it. It took a couple of rides to get use to the increased sound level when you tagged a piece of wood at 20mph.