I hear folks talk about piston slap. Can anyone explain how this happens, even in a new bike ? Does it hurt anything, how can it be corrected.
Thanks Jonnierock

 

it's when the piston skirt contacts the cylinder wall. caused from too loose bore to piston clearance. i've seen some cast pistons with broken skirts but forged pistons will usually last. manufacturers make them that way to prevent cold seize, since the piston expands faster than the bore(especially liquid cooled motors). wouldn't worry too much about it unless you ride at the rev limiter.