This bearing mod comes to us from the master, Eric "YoEric" Wolff...

As the board regulars know I modify LOTS of yo-yos. One of my specialties is transforming fixed axle yo-yos into ball bearing specials (not just to do it, only when this type of conversion makes sense). This is one of my favorites. I do NOT recommend that you perform this mod on a Mardi Gras butterfly that's in good condition with the logo/pog-like discs intact since it's collectable value is too high. However, if you find one w/o the "labeling" do try this mod, it makes for a beautiful, light weight (48 grams), long spinning trickster.

Warning: this is a complex mod & not for the feint of heart:

1.) Remove the original steel axle by cutting through it CAREFULLY with a fine-toothed hack saw and popping out the parts with a small screw driver;
2.) Drill the holes out to 5/32"
3.) Take two Yomega bearing spacers and grind them (or sand them) down from their stock thickness of .110", to .0625". Then cut rings of vinyl tubing (7/16" ID - 9/16" OD or as close to this as you can get) .0625" thick to fit around the outside of your newly ground bearing spacers. You need to do this to increase the OD of your spacers so that they fill the space in the yo-yo w/o leaving any gap;
4.) Get a 1 1/2" long 5/32" diameter bolt/screw (a # 8 screw will do, but you'll have to sand the threads down a bit). Cut the head off the screw leaving 1" - this is your new axle;
5.) Find a 5/32" x 5/16" sealed bearing (a Team Losi bearing is perfect);
6.) Get two #8 (or 5/32") nuts; preferably something nice looking in brass, I use wing nuts or knurled lamp nuts (see picture);
7.) Now you can assemble the yo: nut -- yo-yo half -- spacer -- bearing -- spacer -- yo-yo half -- nut. Just like your garden variety Yomega or Spintastics unit;
8.) For the weight rings: You will notice that there's a groove just inside the outer edge of the yo-yo halves (where the logo/pog-like discs used to fit) get some large diameter solder (yep, solder) and cut 2 pieces about 6" long and bend/mold them until they fit precisely into the grooves (you'll have excess, trim it off so you have something that looks a lot like a TigerShark weight rings). Glue/epoxy the weight rings in place.

You're pretty much done. Sign it with a gold paint pen (you've worked hard enough so that your autograph ought to be on it), string it up - it'll like Slick-6, and go!!!

Oh, make a nice pouch too (again, see picture).......