i was replacing the valve cover gasket on my 2002 Honda 400ex. i noticed the timing chain has been grinding the top of my valve cover. could this mean i need a new timing chain or does it just need to be tightened. has anyone seen this before.
They're know for the timing chain stretching.
The early 2000's crf450r dirt bike timing chain fits and is much better, it never stretches.
When I hopped up mine years ago, I replaced the timing chain at the same time to prevent this.