I searched the net for a bit, apologies for the noobish question...
I was under the impression that valves which are in need of adjustment may be loose (valve clatter) OR tighter than spec'ed clearances (possibly leading to burnt valves); local web board seems to think when valves wear the gap gets bigger hence needing an adjustment, and clearances can't tighten with use...
Engine in question is a honda k20...
