ATV General Discussion 400ex cam chain tensioners September 12, 2015 I’m rebuilding a 400ex that I just picked up dirt cheap. The OEM tensioner still seems fine. But I’ve read a lot of bad things about them. Should I use it or replace, if so what should I replace it with, has anyone used ebay ones? Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window) Related