09 piston hours?

I have had a couple different opinions on when to install new piston on my 09 450. I am a + 40 expert level rider,some say don't go over 40 hrs some say 60 hrs is more than adeqate. I would like to get feedback from other riders on when you changed out your piston and how it looked. btw- I have 45 hrs on my bike. Fresh air filter every ride,never more than 3 hrs on oil change using honda w/moly in engine side.

Thanks in advance Ernie:thumbsup:

It should go at least 100 hours unless you spend a lot of time on the rev limiter. I'm also a +40 Expert mx'er and was able to get 200 hours out of the piston in my '04. My '08 is pushing 100 hours and the valve cover has never been off.

i have used the same maintence schedule as you. changed my piston @ 110 hrs and it looked pretty much brand new. valves were perfect. installed a pro x piston and now have 180hrs. this is on an 08 by the way. always a clean airfilter and fresh oil.

I had 120 on mine and it was worn completely out. There is another thread where Ron Hamp describes what happends when the piston is run too long.

Pretty ugly pics too.

My piston at 120 hours was showing the rounding that RH was talking about.


I put 102 hours on the piston in my 2009 and it looked fine when I tore it apart to do a top end. Everything looked good with the valves except that the coating on one of the intake valves was starting to wear off. I race MX in the 40+B class.

BTW, I was riding moto with pro flat tracker, Willie McCoy, a few of weeks ago. He has an 08 CRF450 with what looks like A LOT of hours on it and he's never had the valve cover off. Willie has a tendency to over-rev his bike so it's a real testament to how much punishment a stock CRF450 can take.

I never changed a piston and all my 450 Crf's (+10) were sold with more than 100 h on. Some even more than 150h. The rod oftenly starts making clicking noises and the engine bibrating before I enen think of changing the piston. My last 08 had its transmission gone way before the piston was replaced. After 50h +/- I find a noticeable lack of power, but never had an engine failure caused by an old piston.

In fact, some people do their top ends after a singnificant amount of hours and put a new piston on an old engine and especially on an old rod. Some blow their engines after a few hours. My point is: if you are not going trough the whole engine, better not to touch it.

I did my top end on my 09 with 95 hours on it and it was still in great shape!!! Could of definitely got some more use out of it... So changing it at 100 hours is definitely ressonable if you do the maintence on your bike like you say.. :thumbsup::thumbsup:

Thanks for the feedback guys-I am going to set my limit at 100 hrs.

Thanks for the feedback guys-I am going to set my limit at 100 hrs.

Good plan :thumbsup:

i had 150 on mine when i changed it. no marks on the piston still within spec. firm believer i have always used recommended factory oils in engine and trans. clean air filter also. love the bike no issued with mine:ride:

122 hours runs great! 2007 supermoto street hours no rev limiter at all

i ride a 250f as you can see by my name and i can handle a 450 i just dont want more weight because i can work the bike better, the reason i say this is so you understand that i am up in rpm's ALOT, i let my piston go for 180 hours. it still could have been ran for a lot longer, but for 125 bucks i just figured its worth it. a 450 top end costs 175-200 so you might as well because it will allow peace of mind for a long time, 180 is a long time and will take a long time to reach that mark and i have literally seen people who have went 325 hours on a mx bike top end. it was at the end of its life, but still, 325 hours!!! most people can go up to 150 hours and have not one problem, that's what i woulld recommend for you, go at least 125.

i think it's hilarious that alot of manuals will say 10-30 hours on a top end, the only rider i think that could even get close to justifying that is barcia. anyways i hope i have helped, good luck with the top end job and i hope it goes smooth when you do decide to throw it in, i am sure that you know this but while you are doing a top end, make sure you throw a cam chain on as well, for 20 bucks it makes me feel really good that everything is gonna work properly for along time

I had at 100 hours on my 08, it looked in great shape. I wouldn't worry about it until at least 100 hours.

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