1998 xr400 bought 4 yrs agao in rough shape but still running strong with a valve clearence check oil change and some upgrades... so new in last 2yrs. mikuni pumper, new CR Hi bars, Q4 exhaust, tires, bark busters, front wheel etc. also fully plated in Coloradowith all the new additions i cant bring myself to part it out.So after all these years.... while in a rush I did the fatal rookie mistake! oil filter in backwards!!!!!one long 3 hour ride and after that it was all i could do to start it in order to move the bike a couple blocks to my new place. never having torn into an engine i pulled it apart last night after trying to adjust the valves with hopes that i could do valves oil change and fire it up but... 3 valves were way looseand adjusted fineBUT the passenger side exhaust valve i couldnt get the feeler gauge under no matter how much i turned out the screw! to me... being un-knowledgeable about inside of engines i notice the cam looks rough...where it sits looks worn and some of the rocker arms look worn and 2 feel sharp on the edges (closest to spark plug)... piston allthough not removed yet looks ok but would like to replace since Im in that deep along with CRF450 cam chain... cylinder/sleeve looks ok to me? and not sure ...what am i looking at needing done given the limited view of pics and knowledge of my fatal mistake??? and if you know a reliable shop that can help me out for services in the Denver area????