After chatting with buffaloon Facebook about it and doing some research I suspect the back firing on deceleration is likely a tight exhaust valve or a crack in the exhaust. After this ride I’m going to switch tonriding the guest bike while I resolve these issues with the k100rs.
bike seems to be running mostly ok but the temperature gauge is readingv much lower than usual. Also the bike isnback firing occassionally on decelleration. At one point it felt like it was hesitating. But otherwise seems to be running ok ... but there is “doubt”