the spark plug is generally located around the engines on the right hand side of the bike, it usually means unscrewing some fairing but depends what bike u have, with the ninja you'll have to take the fairing off. the spark plug will have a rubbery like - hose attached to it, take this off (just pulls off) to reveal the spark plugm use the appropirate spanner size, most likely you'll need a through rachett for this and take out the spark plug. hope that helps
Roger - bike healer
March 2007