Motorcycle Repair: plugs, spark plug gap, center electrode

Question
hi i have an 1982 honda cm 400tc i am looking for the correct spark plug gap for this bike someone toild me the gap should be 032/036 inch but i have since been told it should be 024/028 help

Answer
Fergus, spark plugs are pre-gapped at the factory, usually around .025" which is a common gap for most all motorcycle engines. CM400T have a CDI ignition which can generate a quick and high-intensity spark, but it is somewhat thin and thready, instead of the big blue ball of fire seen with the older battery ignition systems. If you were racing the bike, you can experiment with plug gaps to increase the size of the spark arc, which some engines might like at high rpms, but for normal use, the lower gaps will last longer and ensure a steady spark to the plugs under all conditions.

Spark plugs like an even gap to jump across. Bending the electrode out excessively will cause and uneven space between the center electrode and the grounded tip, which can cause some erratic spark arcing.

Found this chart for you, confirming my response here.

http://www.fortunecity.com/silverstone/brandshatch/876/specs.htm

Bill Silver