How do I adjust the valves on a YFZ 450?

 

pull the gas tank off and take the valve cover off the top of the motor. put the piston at top dead center if you pull the plugs on the side of the motor you can roll the motor with one and line the mark up in the little hole there is a T next to the mark. then take a feeler guage and check your clearences to see what you need for spacing( i'll look in my repair manual in a little while for the specs) then you need to have a shim set so you can put the right thickness in.... if you have that then you need to pull the cams out and pull the silver looking caps up( use a magnet or valve lapper to get them out) that are covering your valves if you looking inside of those there is a little cap up inside you need to take that out and replace it with the proper thickness. once you've done that re-assemble and check your clearences and put it back to gether and go..............later joe31

 

Do yourself a favor and take your investment to a qualified tech for valve adj. no disrespect, but if you have to ask then you probably should not attemt it. removing your cams and properly timing them is crucial and if not done properly WILL result in VERY expensive repairs. If you are experienced or have decent mechanical ability find someone who has done it and have them guide you the first time.
just my $.02
dbr