Recently I have notice that my bike doesn't feel as smooth as it did a couple weeks ago. Tonight I took all the fairings off, replaced the fuel filter and checked the chain. I had the rear tire off of the ground to lube the chain and noticed a screw head in the tire. At higher speeds (90-120mph) I feel a vibe, will a small screw do this and is my tire garbage? Please let me know what you think. thanks.

 

I've had all sort of stuff in my tyres over the years, screws,nails & bloody monster paper clip. It depends, when you say small screw, tyre did not deflate when you removed the screw?. If not, their pretty resilient with this thing, if it hasn't damaged the tyre carcass then you should be ok. If the life of the tyre is pretty close to being replaced, then get it replaced. If the tyre deflated, you can get them repaired, but its something that's always in the back of you're mind about reliability. (I'd replace it), but get it looked at.
If the tyre lost a fair amount of air, then it would definitely have effect on the handling.