Print This Page Print This Page

Spark Plug Sizes

Threads

There are currently three spark plug thread diameter and pitch sizes used on motorcycles and ATVs: 10 mm x 1.0, 12 mm x 1.25 and 14 mm x 1.25. There are currently two thread reaches (lengths) used: 1/2 inch  and 3/4 inch.

doc20040726235413

Never use a spark plug of the wrong reach. If the reach is too short, carbon deposits can build up on the threads of the spark plug hole, plus the spark will not properly ignite the air/fuel mixture. If the reach is too long, the piston could contact the spark plug, plus carbon deposits can build up on the spark plug threads.

Wrenches

There are currently three spark plug wrench sizes used on motorcycles and ATVs, 5/8 “, 18 mm and 13/16”.

 

 

Was this information helpful? How can we improve it?

Your email address will not be published. Required fields are marked *

Table of Contents