Yoyojam Matrixx C bearing/dual silicone conversion

Hey guys, did one of these about 2 weeks ago, and shipped it off. Meant to take pics but forgot! Whoops!

Guy really liked it, so much so that he sent 2 more to do!!! This time I decided to document it so I could show all of you, I’m sure there’s some, “yoyo gearheads” that want to check it out!!

2 Old (2003??) Yoyojam Matrixxs. I brought them to 2013 standard playability by converting to a C bearing & adding silicone. The tough part was the need to add an acrylic ring due to the fact the existing oring/silicone groove starts at ~0.510" diameter, and the bearing is 0.500", and we need approx 0.010" clearance… So the the ring is machined & laminated in place to basically add material.




Check out that old bearing… 3/8" (0.375") Outerdiameter, vs the 0.500" of a C bearing

First step was to highwall it. There was an adjustable gap, the way it worked was the bearing was able to really sink into this side, to a recession depth of near 0.057" or so. I chopped off 0.040", the result is approx a 4.1mm gap.

both sides highwalled

As mentioned earlier, that ID of the silicone/oring groove isn’t thick enough to support a C bearing as is. More material is required. The work around is actually getting more material in there. To do that I’ll use some acrylic stock, cut some rings to size & glue them in, joining them in as part of the yoyo, and then be able to carry on about the mod :slight_smile:

I cut the ID of the groove to get a known dimension, that way I’m not dependent on the mold’s tolerance or other issues (making sure there’s no radius at the bottom of the groove, assuring parallel walls & no draft angle)

Here’s the ring cut. It’s right at the ID of the response groove. Maybe a slight press fit. Some CA Glue and it bonds permanently haha.

Here it is after being glued. Just glued it while on the lathe, then sawed the piece off from the bar stock

After both have been sawed. Next step is to trim down to the same level as the face, & remove the red & blue original plastic to take up from a 3/8" clearance bore to a 1/2" clearance bore.

Post facing, still have to bore it

How it looks after being bored to accept C bearing

Starburst side bored to accept C bearing. Also had to bring the face the bearing mates up to down to around 0.015" below flush, resulting in ~4.1mm gap

Finished both halves!!

Last step was to actually trim the height of the bearing trunion/post down by about 0.015" so that it doesn’t strike the other half of the yoyo, & the yoyo halves actually sandwich on the ID of the bearing.

Hope you guys get a kick out of this!! Once the silicone dries I’ll be able to take em’ for a test drive.

Til next time!


That is extremely impressive work.

Nice work.

You’re my hero.