1971-1973 Arctic Cat Snowmobiles Factory Service Manual, Page 55Get this manual
ENGINE SERVICING (WANKEL KM914B) The intake and discharge of the fuelair mixture and exhaust gases are described and illustrated in the following: At the ignition moment (a few degrees before top dead center, where the chamber volume is at its smallest) intake simultaneously occurs in the preceding chamber between points and BIn comparison to conventional combustion engines: Top Dead CenterMinimum Chamber Volume Bottom Dead CenterMaximum Chamber Volume
This illustration shows the same chambers, between points and A, in the bottom dead center position between the power and exhaust stroke