2001 Ski-Doo Mini Z Factory Shop Manual, Page 113Get this manual
Section 06 ELECTRICAL Subsection 02 (SPARK PLUGS)
SPARK PLUGS
NGK SPARK PLUG NGK SPARK PLUG NUMBERING SYSTEM
Bombardier uses the NGK spark plug brand on all its snowmobile modelsThe heat range identification system is: Low number hot plug High number cold plug