Spark Plug NGK A6, AB-6
NGK Spark plug Part number A6 has now been replaced by AB-6. The plug is the same construction and uses a 21mm spanner instead of a 25mm.
AJS: SV models 18mm, OHV models 18mm.
Matchless: SV models 18mm, OHV models 18mm.
Norton: All SV models 18mm.
Triumph: OHV models 18mm.
Ariel: SV models 18mm, OHV models 18mm.
Sunbeam: All Models 18mm Thread.
Villiers: 98cc 35PD, 98cc Midget, 98cc Deluxe, 147cc Mk 8C, 148cc Mk 12C, 15C. 197cc 1E, 2E, 3E. 197cc Mk 5E. 197cc Super Sports 18mm. 249cc Mk 14A. 346cc 14B, 27B.