Joe Friday wrote on 01/27/09 at 08:00:20:How thick should it be?... I have nothing to judge how much wear has occured... Guess I could pull it out and take a pic of the thing...
Unless you're going to remove the headcover, just eyeball the thing and make sure it's at least worn away smooth and that pieces aren't flying everywhere.
If you're askin' what I did, I took the cover off and replaced it. Mine's a '96 and I don't know about aged plastic. But if I knew I was going back in there in 2 years, I would have left it.
With the next cam chain I put in there (ss.com super cam chain) the next time it'll need maintanance will be to put a new bike on the cam chain.