This might be very obvious but it not only changes the weight but the way it feels and plays. The way I came across this was when I was playing with my Chief something didn’t feel right and I thought that it’s time for a new bearing, so then I decided to test my chief with the bearing that came with my Bonfire (the flat 10ball from 3rd run bonfires) and it played a lot smoother but felt like there was more weight in the center. I caught my attention so then I put the bearing that I normally use with my Chief into my Bonfire and WOW you can feel the difference! Normally I’d describe the Bonfire with a rock feel at the end of the string but with the bearing that I normally use with the Chief changed that! It still felt like how I’d normally describe the Bonfire but it seemed to play faster and felt like there was less weight in the center. I’ve should have mentioned the bearings that I was using in the beginning but the one that came with the Bonfire was a flat 10ball with a very quick break in time, and the one I use in my chief was a center Trac bearing (8ball not the CTX). It really made a difference. The center Trac was cleaned once and lubed once with a very small drop of YYF Thin lube, and the flat 10 ball was only lubed twice with one very small drop of YYF thin lube. I’d say the 10ball was smoother, quieter, and heavier. The 8ball center Trac was lighter, and and louder.
betting a scale would disagree with you… though I suppose it depends on your definition of “significant”… C sized bearings range from about 1.9 - 2.3g… not exactly a huge difference, especially at the center of a yo-yo.
I would fully agree with Kyle. And both Kyle and I have been ‘tweaking’ yoyos for well over a Decade.
I think what you are actually ‘sensing’, is not the actual minute weight differences, but the variations in performance from one bearing to the next.
If a bearing plays a little slower; it may give the sensation of ‘playing heavier’. If you then play the same Yoyo with a quicker bearing; then you may feel that the jump in Speed, makes the Yoyo feel: lighter/quicker on the throw down or in the air.
And it is not just the various bearing types. You can get a tube of 10 C size bearing and even they won’t necessarily feel/play the same, from one to the next.
As Kyle already mentioned; small weight differences at the center of the Yoyo; do not exactly make a huge difference.