Roadrunner1390 Posted March 8, 2013 Share Posted March 8, 2013 I have a 2009 YZ450F with 100 hours on it. I am a medium skilled rider and was going to just put a piston/ring and go the season. I am told that I should replace all valves (new guides, seats ect..) That parts will be approx $500 and labor another $500. Do I need to replace all this ?? RR Link to comment Share on other sites More sharing options...
slice Posted March 8, 2013 Share Posted March 8, 2013 Hi Roadrunner, Welcome to the YOC , might be an idea to do an INTRO (new members section) before launching into a question, only a suggestion but most folks like to have a get to know you BEFORE they will answer questions, just a quirk of this site really but we do get a LOT of one hit wonders (my bike's broke how do I fix it? never to be heard from again) until the next time when they get stroppy cos no one will help out . As to your actual question why do you want to do a top end and piston / ring replacement? is there an actual problem or has someone told you to do this? 100 hours do'es not seem excessive for your bike to require this much work. Or are you burnihng oil and that's a different matter, a bit more info would help as to your reason for the repairs. Link to comment Share on other sites More sharing options...
dt502001 Posted March 8, 2013 Share Posted March 8, 2013 Hi RR as slice said best to post a hello. But as for your? the valves should be replaced they strech and you don't want them breaking,also because of the spring pressure the keepers will have started to wear the top of the valve. The guys running the 450's around here all go with a 10 race schedual of valve replacement,but not guides and seats just check the bore of the guide and resurface the seats if needed. As for the pistion and rings the pistion is probably fine but for 60 bucks I would change it anyway and 100hrs the rings should have been done 2x by now. I know a grand seem alot but if the valve breaks then your looking more like 3000.00 to fix it. A grand is just about normal to freshen up a 450 Slice they burn oil from day 1 all of em 250's and 450's, when I first got mine I kept looking for a leak thinking it couldn't possibly burn that much oil,wrong no leak normal,I top up the oil and check the gas . Link to comment Share on other sites More sharing options...
slice Posted March 8, 2013 Share Posted March 8, 2013 Thanks for that, you learn something new every day! Link to comment Share on other sites More sharing options...
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