Why: Because they're suppose to work better in the rain.
Time: 3-4 hours (does not include removing and installing wheels).
Tools:
drill press
1/4" drill bit
3/8" drill bit
5/8" counter sink
cutting oil
big cardboard box (to catch all the oil and metal shavings)
As far as a pattern I just traced the diameter of the rotor onto a thick stock piece of paper (important to use thick stock) and then started to divide it up like a pizza pie. I didn't have a protractor or a compass, but it is possible to do a decent job with a ruler (if you were paying attention in geometry class). I then measured and marked where the 3 1/4" holes and 2 3/8" holes would be centered to have overlap across the rotor surface. I stayed about 1/8" away from the outside even though it appears that the front brake pads ride out there. I then cut the ring out and taped it onto the rotor and punched the center marks.
Before you punch the second front rotor - make sure you line up the mount holes and align the patterns on both rotors - if you want them to line up that is. If you do a swirl pattern you'll have to reverse it to match the opposite side.
Now it's time to set up the drill press. If you have a bench version like mine, put it in a big cardboard box to catch the oil and metal shavings - it's very messy by the time you finish. I also clamped a 3/4" piece of plywood. You won't need to clamp down the rotor - just hold it in place when you drill.
Key Points:
Set the drill to the slowest speed you've got (400-600 rpm).
Don't use a lot of force - let the bit do the cutting.
Use LOTS of cutting oil.
Even after drilling all three rotors my drill bits were still sharp (get the best ones you can). Use the counter sink for a few seconds on each hole to get a small bevel on the edge.
Wash them like you mean it. I then took a wet emory cloth to clean up the rotor edges and discoloration on the surface.
And that's about it.
They also look a lot cooler.
. Seriously, nice job. Let me know how they do in the rain. There is serious room for improvement in the braking ability of these old wings when riding on wet roads.
