rod play

Joined
Apr 11, 2001
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#1
I'm in the process of rebuilding the top end on my bike (kdx 200) and was wondering what the tolerance is on the rod sideplay. When I hold the rod I can wiggle it from side to side. This is my first time doing this so any help would be appreciated!!!
 

Sage

dirtbike riding roadracer
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#2
side to side play is ok, if you hold it over on one of the thrust washers and pull up & down on the rod it should have NO play.
 

nikki

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#3
Exactly what Sage said! Side-to-side is normal; up-and-down is time to replace the bottom end bearing and connecting rod. You will usually hear a pinging/tinging noise when the bearing starts to wear. Sunds like your bike should be fine, though.
 
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#4
Thanx, I was hoping it would be okay. When i got to reading the instructions on my new wiseco piston it said something about drilling holes in it on the exhaust side for added lubrication. I called the local shop and asked them about it and the said wiseco pistons are about all they ever use and they haven't heard of that. Have any of you heard of this and do you do it?
 

nikki

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#5
YES!!

I had a Wiesco go bad on me once in an RM 125 (the pin where the ring meets together came up through the piston top) and I was told by a factory Suzuki mechanic that you should widen the holes that are already in the piston. There should already be 2 or 3 holes on the exhaust side of the piston, I think... and you can take a small drill bit and gently hand-twist it from the inside of the piston to widen the already drilled holes (make the holes nice and smooth of course). This will allow for better lubrication and help avoid problems. I have been doing this ever since mid-'99 and no top end problems since!
 
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#6
I see someeone has just answered but I'll leave msg as is.

The idea is to create an oil reservoir by drilling a dimple or hole on the front of the piston usually aligning with the bridge (or bridges) of the exhaust port (which are naturally heated by exhaust gas & have a bad heat path to cool them). I would only bother on an engine that was prone to seizing at this point. In the bad old days when bridges were first introduced this was not too uncommon, but I don’t believe this to be a kdx flaw, mainly ‘cause the kdx doesn’t have a thin central bridge.

Feel free to shoot me down if you know better.
 

BRush

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#7
I don't believe the 95-01 KDX piston requires any drilling. The Wiseco instructions that came with my big bore kit were a bit ambiguous, so I called Eric Gorr to confirm. He said none was required (there's no exhaust port bridge).