Hi ya fellas! Just bought a -05 450F YZ with 35 hours on it (unfortunately not sure about those hours and don't know anything of it's service history). I'm about to change the timing chain and I'm concidering to change the piston rings too. I allready have the rings and gaskets so the costs won't rise, but is it worth the work that it will take? The bike looks quite good and I believe those hours are right. I concider my self as a intermediate rider and I have to apologise my bad english cause I'm from Finland. Thank you for your answers!