Hey guys!.....When do yall think I should replace the piston and rings in my 06 yz450f. It has 34 hours on it and It has never had the piston and rings refreshed,it still starts great(about the third kick)and the kick starter seems to have pretty good compression. I just checked the valve clearence the other day for the first time since I bought it new and then had my friend that owns the yamaha shop and is also the mechanic to double check the clearence to make sure I was right and the valves were fine......right in spec:thumbsup: . But he said I should put a piston and rings in it soon.........he said yamaha recommends doing it about every15 hours or every fifth race put in rings and every tenth rings and piston:jawdrop: ,That just seems to be to soon for a 4-stroke and for my likings and I thought these four strokes were to be bullet proof. I told him that I seen somewhere they said to do rings and piston at 50-60 hours and replace the timing chain if needed,He said if I were going to do much riding and racing this winter I should do it by atleast september. So guys what do you think? Iam a 30+B rider and race about 15 rounds a year in the Mega Series and right now this weekend is round 10 and was wondering if it needed freshed up by july 10th or just wait till sometime in august.....Like I said it has 34 hours on it,......is that to long to go without replacing rings and piston?