What to do to a 2009 Yz450f with 200+ hours?

6 replies to this topic
  • rcdude33

Posted March 11, 2013 - 06:45 PM


Hey guys!! I got a 09 yz450f which is an absolute beast and has been such a reliable bike. the bike still starts first kick most of the time and its been running pretty good. Its got a Drd exhaust and a jd jetting kit.

So i took it out the other day and ill be nest it was feeling a little sluggish, like it didnt feel as snappy but maybe it was just me. But i clean my air filter every ride and oil with filter every 8-10 hours.

So heres my question, what would you guys replace motor wise since i got this much time on this beast. I definately need to check the valves but would i gain any power by throwing a top end in it? BTW i already have all the parts needed to do a top end. But if my valves are in spec should i replace them? I heard the intakes are usually good to replace but im no that sure.

BTW i ride woods and im getting ready to race this season!! But hey thanks so much for your time and i hope i can get this bike running as good as new again

thanks and god bless!!!


  • hackman162

Posted March 11, 2013 - 08:48 PM


Split cases and do bottom end bearings and seals. New crank assembly. Inspect all gears and shift forks. New piston/rings. New timing chain. New valve seats and seals. At minimum on the clutch side, clutch plates but may need basket,etc depending on wear.

  • Family Man

Posted March 12, 2013 - 07:52 AM


Time for a new piston and wrings and wrist pin for sure. If the head is still in spec I don't think you have to re do the valves, now.

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  • rcdude33

Posted March 12, 2013 - 11:18 AM


yeah im definately going to be putting a top end in this week for the weekend. But will i notice really any difference in the power? Like i know its a 450 haha. But if the valves are in spec should i just replace em>? or just leave them be?

  • Family Man

Posted March 12, 2013 - 08:05 PM


A new piston should make a noticeable increase in power and compression. Make sure to follow the manual as exactly as you can.

  • rcdude33

Posted March 17, 2013 - 08:06 AM


Ok i threw the new top end and it is running awesome. BUt it seems like it is leaking a little oil by the ignition cover and the oil is by the bottom of the cylinder by the filler cap. I check the bolts and they are tight but would it be better to replace that case gasket? We torqued everything to the manuals specifications as well.

  • hackman162

Posted March 19, 2013 - 08:00 PM


Dumb question, but is the o-ring still on the filler cap?

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