22 hours or so on a 2014 YZ450F. Manual gives useless interval recommendations for certain things, like pistons, chains, tensioners. "Replace the piston every time you run it up and down the driveway" basically.
What's a safe replacement interval for the chain and tensioner? The chain itself is easy enough, and I don't mind the $20 cost for it. Reading about people getting kinks in them by 60 hours or so. Would sooner be better? Every 40-50 hours?
The tensioner looks like a PITA behind the exhaust pipe. When are people replacing those?