1978 Polaris RXL Service Manual, Page 28Get this manual
COMBUSTION -
NO RMA and BNORMAL
Th power in an internal combust io engine is developed by ex pa nd ing gases result ing from th burning th air fue chargeIf yo have th proper air fu el mixturetiming is correct, and th an ti -knock (octane rating) quality of the fu el meets the engine requirements, the burni ng proc ess shou ld occur evenly and stead ily Th is is nor mal combustion cy cle wh ich will be repeated many housands of times every min ut he engine is in opera ion