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cr 125 pre dilled pistons wiseco?prox?vertex?

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which one has the pre drilled oil dispertion holes because i do not want to do it myself,thanks:thumbsup:

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i have a wiseco piston that im going to install after i get my cylinder back. why do i need to drill a hole in it and where am i drilling it? what size?

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Very specific instructions come with the piston (if they are not already done). If not, they have it on their website.

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so vertex and pro x are cast? also what about namura tech?

I believe all pistons are cast except Wiseco. Oem, Namura, Pro-X, Vertex I believe are all cast and require no holes

i have a wiseco piston that im going to install after i get my cylinder back. why do i need to drill a hole in it and where am i drilling it? what size?

I think why you have to have to holes is to cool down the exhaust bridge. The reason you have to have to holes with forged pistons is because they do not hold the oil as well as cast pistons.

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I believe Wiseco would add the holes from the factory if it were possible. When I was working on several cr 85's I thought I would be smart and pre-drill the holes so it would be easier to switch a piston at the track. I predrilled a total of 4 pistons...2 for each bike.

The holes only matched on bike "A". Bike "B" had the bridge of the port several millimeters off. It would have still worked, but the holes would have did no good as they did not match up to the bridge. All of the bridges are not in the same place.

None of them matched the new oem cylinder we had to buy for one of the bikes.

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My 02 CR125 Wiseco came pre drilled.

Dude, if it doesnt have holes, dont sweat it. Drilling them is easier than cleaning your filter

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my piston is down at racerstoystore.com

he's replating my cylinder and re working my head since its got so many pits in it. he's going to ceramic coat the head for heat resistance too. i'll call him up and have him drill a hole for me because i sure as hell dont wanna do it.

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I was a little scared drilling into my new piston too. It only took a couple of minutes. It's not like you are drilling a very big hole. If you follow the instructions it will be pretty hard to mess up.

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i just got my weisco piston and have to drill the oils disp. holes also. what kind of drill bit should i use on this thing?i know the size from the instructions but i have to buy some drill bits and never had experience with bits!!!

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Wiseco Instructions say between .060" and .090" which converts to:

1/16" to 5/64"

Small drill bits. I used the 5/64" on mine.

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