It wouldn't be a GS if there weren't a few rattles here and there.  Mine does it continuously, especially in the summer.

If you want a quiet engine, buy a Kwakasaki Ninja 500.   

I would almost bet, 89-95 bikes have this show only with increasing mileage. 35K was the first instance on my much used and abused 89.
GeeP - you're dreaming. EX's are a lot worse for a lot of things including a motor that just doesn't vibrate right. Its oddly quiet when you least expect it too.
Cool.
Srinath.

Endplay ? All this attention over some endplay  ? It's really not an issue. If the noise bothers you, spend the time and money to correct it, and maybe it will stay away a while.

I'd bet if I were to pull valve covers and setup indicators on all of my engines I'd find they were all out of spec somewhere. That doesn't mean I'm going to start breaking seals and 'fixing' an unbroken engine.