400ex Valve adjustment

[MxDale71]

Ok, a friend of mine has a 99 model 400ex that probably has never had the valves adjusted. When he starts it , it makes a terrible rattling noise and I'm guessing that it's the valves but I'm not sure since I really wouldn't know what to listen for. I've never adjusted the valves on anything and I was wondering if someone could explain it to me so I can help him. I want to be the one to do it so that I can maybe learn how adjust my own on the dale when it needs it, but I wanna practice on my friends quad first ;) :D. Is it a hard job? I was givin a link that shows you how before but I lost it. Should it just be left to the professionals or could I probably do this somewhat easily for my first time?

[Pappy]

just click on the extech icon on the top of the screen....simple job...no problems

[L.Vegas400]

i just checked and adjusted mine about a week ago. i used the instructions of this site and worked perfectly. mine were about .001 off. very slight adjustments. i found if you bend the end of your feeler gauge 90deg it works great.
just my $.02

[400exbat]

I just did mine this weekend using the guide on this website. It was a peice of cake. MY 99 400ex had never had the valves done. The intake valves were perfect and the exhaust valves were about .001 loose. just take your time and its real easy. I had never done valves before but I would do it again now.