having a issue with my kholar, Kolher command 46CI v-twin Ohv when cranking over it will not start but every now & then will almost like backfire out the exhaust. The flywheel key is good crank key is good, timing is all neutral & leak down test passed no leakage past valves, got spark & fuel, no bent push rods valve train is good, has new 31 coils. anyone have any other input that may help? was running great then all of a sudden would not start back up.