There are two ways to tune a Side Effects yoyo. The first is to take the yoyo apart, push out one of the Side Effects a little bit and rotate it about 45 degrees (about 1/8 of a turn). Reassemble, screwing together tightly, tighter than you would for a non-Side Effect yoyo, you won’t strip it! Test, and repeat until smooth.
The other option is to try a different set of Side Effects, and do the same tuning techniques.
Also, you want to make sure the important parts of the yoyo are very clean before reassembling. This includes the bearing recess and the tapered hole the Side Effect fits into. Take the yoyo apart, wipe the bearing recess with a cotton swap (Qtip), also wipe the tapered hole for the SE. If the o-ring on the SE feels snug and squeeky when you insert it, use about 1/10 of a drop (+a really tiny, tiny amount) of V4M, or other light lube, on a Qtip and wipe it around the tapered hole after cleaning. This will help make sure the SE properly seats metal to metal when tightened. The amount you put on a swab is almost non-existent, you’re not trying to make the inside of the taper wet, just leave a microscopic film of lube. Sometimes a dry/dirty/slightly out of spec o-ring may not want to slip into its retaining groove in the taper, causing the SEs not to seat properly and fully, resulting in vibe.
Any other questions?