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ROTM Winner
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Discussion Starter #1
I know it's not a raptor but it is a yamaha and I know there are some good guys around here who will help me out.

So I bought a PW50 for my son and noticed a sound coming for the head. Sounds like a clinking.

Here is the noise
http://youtu.be/4GElO7auVcY

Took it to a buddies and we pulled the head. This is what we found.




My question is should there be a lot of side to side play in the piston on the crank shaft and should the crank shaft arm have any side to side play?
 

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www.gtpoffroad.com
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2,576 Posts
The piston can move along the wrist pin, a little. the rod can move a little side to side.

is that a groove on the cylinder?? that's not good.
 

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I may be getting older, but I refuse to grow up!
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10,476 Posts
It's to late for this, but, that may have been a exhaust leak. Good that you got it apart though. It looks like you need a bore and oversize piston. Yes, the piston will slide on the rod, and the rod will slide and rock on the crank. But, there shouldnt be up and down movement of the rod on the crank. Be sure the bearing is oiled when testing.
 

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ROTM Winner
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Discussion Starter #4
It's to late for this, but, that may have been a exhaust leak. Good that you got it apart though. It looks like you need a bore and oversize piston. Yes, the piston will slide on the rod, and the rod will slide and rock on the crank. But, there shouldnt be up and down movement of the rod on the crank. Be sure the bearing is oiled when testing.

Your saying the clink sound may have been a leak?

I can pick up a top end kit for rebiuld kit for like $150. I noticed the play in the piston and rod and wasn't sure if that was normal. No point in relpacing the piston, cylinder and head if the play in the rod is going to mess it up again.
 

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ROTM Winner
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Discussion Starter #5
Got the new plastics and graphics came in today.




Should be getting the new top end in tomorrow. I picked up a big bore 60cc cylinder and piston. Lol
My sons first machine is gonna be a modded moster. Haha. Is it fair he gets engine mods and not me?
 
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