Applying a modicum of logical thought to the valve clearance question. I 
agree a regular check is desirable and believe that the hazardous side of 
wear would be when the seat/valve wears and the clearance decreases. This 
will rapidly lead to increased seat wear, valve burning and major repair 
bills. If the valve train wears or screws creep the result is increased 
clearance giving more noise and increased wear if ignored but no major 
repair hazards unless ignored for a really long time. Any suggestions for 
recognising decreased clearance without need to remove rocker covers?