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Search the Dirt Rider Forums:how can you tell for a bad crank
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just a ? out of the blue :D
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First of all, for what bike?
A guaranteed method to check if you need a bottom end rebuild would be to remove the cylinder and try moving the crank, some horizontal play is good but any vertical up or down free play is a sign you need to rebuild.
Remove the flywheel cover and try to wiggle the flywheel, if there is any play, that is also a sign.
You should be able to tell just by listening, if its bad enough. A slapping sounding will be audiable, much more distinct then the famous two stroke "knock"-----------------------------------------------------------
"Be nice to your mechanic or make sure to double check your axle nuts"
No cams, No valves, No problems
-2000 Yamaha YZ125 -
i would say a bad big end bearing makes more of a heavy knock or clunk than a slap sound. but usually the bike will sieze up before the bearing gets loose like that.*********************
Winning is 90% rider and only 5% bike, the rest is luck -
I know this is old but I just bought a 2002 cr80rb with a blown top end nd a "blown" bottem end supposedly..I tried to move the flywheel up down, side to side nd got no excess play but when I take the rubber mallet nd tap the con rod when it's at the bottom of the stroke I get the "clank" people talk about..so what is my problem exactly? thanks guys
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does the rod move smoothly around the crank pin with no up and down play? if so then your rod bearing is ok for now. if you're unsure, replace it.
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Winning is 90% rider and only 5% bike, the rest is luck
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