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2008 CRF 450 - 80Hrs on it, Time to Freshen it up! Thoughts and Comments Please!


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Chk your compression if good and no other problems I would leave it alone for now...I have an 07 with just over 80 hrs, and valves chk out fine every time..it still a beast!

good advice, the manual indicates what the comp. psi should be accounting for the decomp. Could also pull the top end off and mic the piston/inspect but at that point you might as well at least re-ring. Easy starting point that will give you a reasonable indication of the health of the top end is a compression test.

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  • 4 months later...

This one can have great compression with a overused piston.... if your ring seal correctly. It's great to check compression some time, but don't overthrust this test. So, if you not abuse your engine too hard you can usually run 100 hours on a piston kit (on a very well maintened bike)...

You surely can run a lot more, but if your piston is too used, you gonna wreck the cylinder wall too... so, change it at 100 hours, inspect the cylinder and bottom still a great deal in my world...

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Most weekend warriors can go 150 hours on a CRF450 piston as long as they don't bake the oil, overheat the engine and/or suck dirt.

That's me, and im runnin at over 600 original hours on original internals, other than valves. Still good compression, but i also changed the oil after every 5 hours, and the filter after every 10.

So in other words, dont touch it!

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That's me, and im runnin at over 600 original hours on original internals, other than valves. Still good compression, but i also changed the oil after every 5 hours, and the filter after every 10.

So in other words, dont touch it!

This is bad advice.

Just pulled the Piston out of mine with 120 hours on it. It held a 1% leak down. When I took it apart, I was blown away at how worn the piston was. The bore looked new, not even a glaze, but the piston was worn clear out. How it held a 1% leak down, I'll never know.

If youve got the time and money to put a new piston in it at 80hrs, go ahead and do it.

I put a 13.5:1 piston in it and am really happy with how friggin amazingly hard it pulls.

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That's me, and im runnin at over 600 original hours on original internals, other than valves. Still good compression, but i also changed the oil after every 5 hours, and the filter after every 10.

So in other words, dont touch it!

Is this from the quess-a-meter? Or actual hour meter?

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You can have good compression and a worn piston skirt or a worn piston pin. If the piston starts wobbling around then you will ruin your bottom end requireing you to split your cases for a new crank. Remember all those brass shavings in the oil filter posts? At 10,000 RPM wear is greatly excellerated when clearances open up.

You will sleep better after installing a new piston, pin and rings, than if you just add rings at 100 hrs. Once you see the quality of a new piston you'll soon forget about the cost.

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do you have an hour metter....600 hours on a piston... I still can't believe it...

Believe it.. I had a hour meter up til 450 hours, and iv'e charted the rest down, and its around 600 - 650 hours on it.

You don't need to be rebuilding your bike every 50 hours, unless your ridin the sh*t outta it, and not maintaining the bike properly. I ride my bike in trails, and do oil changes, filter, and air filter changes frequently. I guess thats how I get the hours I do out of my bike?

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Believe it.. I had a hour meter up til 450 hours, and iv'e charted the rest down, and its around 600 - 650 hours on it.

You don't need to be rebuilding your bike every 50 hours, unless your ridin the sh*t outta it, and not maintaining the bike properly. I ride my bike in trails, and do oil changes, filter, and air filter changes frequently. I guess thats how I get the hours I do out of my bike?

I would strongly advise you to check engine parts for wear, and make sure engine parts are within spec.:excuseme:

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