2003 Heritage Softail: The good old days, a wire brush, sand paper and re gap. I know now my manual calls for "Change Spark Plugs" at 10,000 miles Service. I have 5500 miles and I was hearing a funny clicking-knocking sound when engine was cold. I went ahead, removed spark plugs, used a wire brush and sand paper to clean electrodes, checked the gap and files the edges of the pin. Re installed them and everything sounds great. Engine sounds better and smoother. Wrong? Right, any other comments?

 

The sparks plugs should last for 10,000 unless there is fouling.
Spark plugs are not expensive,I would rather buy new ones instead of cleaning them IMO.
The only time I would clean them is if I was in the middle of no where and had no choice.

 

Plugs fire from the 90 degree edges on the electrodes. Anything that rounds them off is shortening the life of the plug. For the few dollars it costs to replace them, why would you even bother.

 

I usually change stock plugs at 5k. Tim

 

Actually i did not round the edges but made them sharper on the edges of the right angle pin and it makes them perform better. I personally think it is a good idea either to clean them or replace them every 5 K and for sure replace them every 10,000

 

Filing the center electrode flat is a good thing because it requires less voltage for the spark to jump the gap from a sharp edge than a rounded edge. I've changed mine at 10k but there was nothing at all wrong with them. They make a very small sand blaster that will definitely clean all deposits from the porcelin where shorting occurs. If the porcelin gets coated with deposits, soot or unburned fuel (too rich a mixture) the spark will crawl down the porcelin to ground rather than make the leap across the gap. These sand blasters used to be bought on the tool trucks or old type auto parts stores.