Drilling Holes in Piston for Lubrication, Best way?

[joeym4130]

I have a RM250 and the Wiseco piston I got said to drill the 2 holes in the piston for the lubrication between the 2 powervalve ports.

The last piston didnt have it, but I could see where there was extra wear on the piston from the absence of the drilling in that small area where the bridge is on the cylinder.

What is the best way to do this, the actual drilling? I don't want to take like a center punch to the piston, it just seems like a bad idea, but I also dont want the drill to be going all squirrley when Im trying to do it. Any tips on how to do this cleanly?

 

[John Cena]

I think a bench drill press would be best.

 

[Jaybird]

Making a center point with a punch and hammer should not be a problem as long as your hammer isn't a sledge. It only takes a slight tap.
If it freaks you out, you can always go to Sears or a farm supply and buy a spring loaded center punch.

 

[Zenith]

Just start with a small bit. Being aluminium you'll find it very easy to get the hole started without going squirly. Just take your time drawing the lines and marking the spot for the hole dead centre...

 

[+30]

Im with you I dont like the centerpuch idea, who knows what stress it puts the skirt under or if it sets up weak spots, you can easily do this with the press, or go very very slow with you reg drill until you have a dimple, I have even used the bit in my fingers to start a dimple in aluminum, it does not take much to provide a point to center the bit.