A friend is making a electric bike and he would like the bike to have a sound like one with a combustion engine, so I am trying to adapt this project for this purpose.

In this video the engine sound is looped continuously.

The plan is to play a sound when the motorbike is tuned on to simulate the engine starting, then loop the engine sound with a rate proportional to the throttle or the motorbike speed and play a third sound when the motorbike is turned off.