Hi all, newbie here this is my first post. I've been lurking for a while and think I have found a bike I like. It's an '01 520EXC with a bunch of extras and the price is right. Now for my question, it seems to me I read some time ago that there was an upgrade to the cam or a thrust washer, or cam gear or something that should be done to the older engines. I can't seem to find where I read it. Can anyone point me in the direction, I would like to do it as soon as I get the bike before I even hit the trail. Thanks in advance.