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Anyone know how to check if crank is bad ?

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I have a 09 rmz 450 ,out a new piston in it , the cylinder on the front and back where woren , and now i am getting a strange noise outof engine , like chain slapping but cam chain is tight , also some metal filings in oil and filter ?

thought it might be crank bearings or something , was wondering how to check ?

or what else could be the problem :worthy:

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There should be no play on the crank going up and down. It should be tight.

But there is play in the crank from side to side. As far as the chain noise.

Check your cam chain adjuster, could be stuck or bad or your guide cam chain

blocks could bee worn out.

Hopes this helps you.

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Yes a guy who seems to know a lot on here said if ur motor is all back together take out spark plug n find something smooth n clean n push down on to top of piston n if it goes down at all crank bearings are bad n another indicator is shavings in the oil n filter... Sounds like u have problem... Crazy thing if u search on here many owners have been having this issue with cylinder way flaking n crank bearings going out... I'd call n complain!!!

How many hours on bike before u changed piston?

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a 2009 450 should not have crank or main bearing failure yet, unless you ran it low or out of oil. What color are the flakes in you oil filter pleats? If copper/bronze colored then you have a main rod/bearing faliure. check your cam lobes/journals, buckets, head, cylinder plating etc for scoring or wear.

The sound could very well be your crank/rod bearings failing but it is hard to believe you have that may hours on it yet. How many hours do you have on the motor?

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when i replaced piston , cylinder head lots of wear on it , but i did nt take time to spec , :worthy: wish i had , so i re ordered new piston rings etc and am going to have cylinder replated .

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this does not sound like rodbearing failure. You said that you just did a top end rebuild? I would take the top end apart again and recheck everything per the manual. To rule out the crank you should check it as described in the owners manual. It is not impossible to wear out a 450 crank in 50 hours but I would bet that it is highly unlikely. A 250F yes but not a 450 unless you are racing it in the A or Pro class.

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I'll bet you have some bad cam journal wear on the head and one or both cams are sloppy when capped and torqued. see if they have any play after the caps are torqued. I have seen this but usually not at 50 hours.

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my bike is 07 but the condition you describe is the exact same as mine. wear on front and back of cylinder and excessive noise. I let it go thinking it was just valve train noise but i started noticing more than normal metal in the oil and filter. I cracked the cases and the big bearing was going. I recommend you do the same. run a magnet through your oil to see if they are magnetic.

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All I can say this sucks because u r about the 6 or so guy on here in the last few months talking about cyclinder flaking n crank bearing issues... N believe it or not all have been around 50 hrs...

Is this happening because of crappy out sourcing cranks? N why is the plating in the cyclinder not lasting?

Just frustrating n not making me wanna get a 2010 unless they change crank brands n start plating the cyclinder right...

I think u should call Suzuki n complain if all ur maintaince is legit n good..

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