compression stoke question

[kfx400isdashiz]

oki have a 03 kfx 400 i am rebuliding. the question is does the spark plug fire everyrotation of the motor or does it hold off on the compression stoke?

[lghickman21]

it holds off til the end of the powerstroke then fires.

[GPracer2500]

The plug fires on every revolution of the crank.

The ignition system doesn't know which stroke the engine is on--compression or exhaust--it just fires the plug when the piston reaches a certain point during it's upward movement. That point is usually around 30 degrees (maybe give or take 10 degrees [shrug?], depending on the engine) of crank rotation before the piston reaches TDC. When the plug fires on the exhaust stroke nothing happens because there is nothing in the cylinder that can be ignited.

The spark on the exhaust stroke is often called a "lost spark".