Kawasaki S2 Mach II
{{Infobox motorcycle
| name = Kawasaki S2 Mach II
| image =
| aka =
| manufacturer = Kawasaki
| production = 1972-1974 model years
| predecessor = 350 cc Kawasaki A7 Avenger
| successor = 400 cc Kawasaki S3 Mach II
| parent_company = Kawasaki Heavy Industries
| class = Standard
| frame = Double cradle (tubular)
| engine = {{Convert|346|cc|abbr=on}} Air-cooled 3-cylinder, two-stroke, piston port
| bore_stroke = {{convert|53.0|×|52.3|mm|1|abbr=on}}
| compression = 7.3:1 measured from upper side of exhaust port crankpins at 120°
| transmission = Chain driven 5-speed (5 up) 2.86-1,79-1,35-1,12-0.96 :1
| rake_trail = 62°, {{Convert|109|mm|abbr=on}}
| suspension = Front: inner spring telescopic front fork
Rear: swing arm with twin three-position preload spring shock absorbers
| wheelbase = {{Convert|1330|mm|abbr=on}}
| length = {{Convert|2010|mm|abbr=on}}
| width = {{Convert|1095|mm|abbr=on}}
| seat_height = {{Convert|800|mm|abbr=on}}
| fuel_capacity = {{Convert|14|l|abbr=on}}
| related = Kawasaki S1 Mach I, Kawasaki H1 Mach III, Kawasaki H2 Mach IV
}}
The S2 Mach II is a 350 cc Kawasaki motorcycle introduced for the 1972 model year and discontinued at the end of the 1974 model year. It has a 3-cylinder two-stroke engine with a displacement of {{Convert|346|cc|abbr=on}}, and superseded the rotary disc valve twin-cylinder Kawasaki A7 Avenger.[http://www.ridermagazine.com/style/vintage/retrospective-kawasaki-350-s2-mach-ii-triple-1972-1973.htm Retrospective Kawasaki 350 S2 Mach II Triple 1972-1973] {{webarchive|url=https://web.archive.org/web/20141222231328/http://www.ridermagazine.com/style/vintage/retrospective-kawasaki-350-s2-mach-ii-triple-1972-1973.htm/ |date=2014-12-22 }}, Ride Magazine, 2012-12-4.