Originally Posted by NJ-Brett
Even some systems on cars would pulse the injectors with a closed intake valve, the mixture just hangs around before being sucked in.
Some bikes must do that as there are no cam position sensors and there is nothing to tell between TDC on the power stroke or the exhaust stroke.
Any thumper without a cam position sensor would HAVE to do this.
The computer can be programed to sense when the combustion stroke happens by monitering the increase in crankshaft speed. With the proper software it is possible to fire the injector at the corect time with only a crank sensor. Some cars do this when the cam sensor fails so they cam still run in limp in mode...