SJ BurnKick mixup inconsistency (Buffering Question)

(Sorry if this belongs in the general discussion/quick question, but if we reach a solution then I think it would be nice to have a separate archive)

After starting this game and becoming semi-competent at viper 2 years ago, I ended up being busy and not playing much until the last month or so. After coming back I sucked a lot, but have improved greatly in the last few days in the lab.

One thing has ALWAYS bothered me though, and that is doing SJ->BurnKicks consistently. For example doing cr. :mp: xx :hp: TK-Feint -> Crossup Burnkick seems like something I can get about 75-80% of the time. 75-80% when failure means eating an ultra or otherwise damaging combo is unacceptable. The strange part to me is that sometimes even when my input looks more clean on the readout in training mode, I superjump with a :lk: / :mk: / :hk: instead of burnkicking.

In combo I always:

This is 100% consistent when I do it correctly and works great for finishing FFF or hitting people from midscreen with :mp: / EX seismo.
However, I’m too slow to do this off a :hp: TK-Feint, not enough frames to buffer the jump and still be low enough to hit crouching targets, so generally I try to do:

This is the motion which seems truly inconsistent.

The two things I’ve heard mentioned pertaining to this are:

Does anyone know for sure how the buffering system works? If I could get a technical explanation it would help me greatly in devising a motion to practice.
Also, I see a lot of viper replays / VODs with the input: :qcb: :uf: :qcb: + :mk:, do people actually do this consistently on stick, or is that pad only? If it can be done 100% on a stick then I guess I’ll just focus on learning to move that accurately+quickly.

It’s difficult to say what the problem is without seeing a video or checking your inputs, I do down back up forward then half circle back (but generally if you’re getting a normal out instead of a bk you’re probably hitting the kick button to fast) The first note you brought up is most likely talking about instant bks which requires Viper to be moving or crouched to get rid of a possible superjump.

:db: :uf: :hcb: :mk:

This motion works great, except that I generally whiff above their head because I go too slow, and when I do get them low it’s VERY rare I can hit a crouching target with them.
If you’re still around do you throw your stick? I play square gate and generally try to keep my motions along the edge to get them super consistent (Really easy to use the timing of sliding a :qcb: for FFF timing etc). I feel like this is only possible by doing the motions super quickly without throwing the stick, but when I do that it seems like I go too fast for the motions to register.

Maybe I’m just bad :B

As a PS: I know people generally use the initial direction for IA BKs, but it does seem to make buffering a regular SJ burnkick far more consistent, it just slows down the input and wastes like 3+ frames before you start the jump.

I throw the stick if you you’re not getting it fast enough you can try down back, up forward,up, up back, back (I don’t know why this works or if anyone else knows about it) but it’s less inputs so it should be faster if you can get used to it.

Thanks man - I’ve been struggling with this one!