If the kick start, often known as a kick starter, on a dirt bike gets stuck and the engine will not turn over, the problem could lie in many different areas, including the gears of the kick start, or within the engine itself, such as seized pistons or a seized transmission. Determining the problem requires an understanding of the engine and its components, so having a manual nearby for reference is helpful.
When attempting to start a dirt bike engine with the kick start and discovering it is frozen, avoid the temptation to kick harder as this can lead to serious damage. Instead, put the engine in neutral and carefully push the kick start. If it moves without hesitation, the transmission, rear brakes, drive line and chain are not the issue. Put the engine in top gear and push the kick start again. If it moves and the engine starts, the engine itself is not the problem. This means that it is the kick start gears that are stuck and will need to be repaired to restore reliable functionality. Applying penetrating oil and allowing it to sit releases the pistons and lubricates the gears to get the kick start working again.