1. Practise with hands separate. When joining hands, use the maximum speed you achieved with your
slowest hand (usually the left). If this speed is too slow, the way to push the speed is not to do it with hands together, but with hands separate. You will always be able to play faster with hands separate than with hands together, so by increasing the speed of your hands separate, you will automatically increase the hands together speed. (the Chang book that Richard W suggested above will describe this in great detail).
2. The main difficulty in the bars you mentioned are the jumps between figurations. One (or both) of your hands may be hesitating minimally at such jumps. This may be completely unconscious, so you don’t notice it. If that is the case, here is one way to deal with it (it is a good idea to do this anyway). Practise the passages that are giving you trouble (both HT and HS) by deleting the demisemiquavers figurations and practising just the outline below:

Once you can do this with confidence (practise not in order to get it right, but in order to never get it wrong), put the demisemiquavers back in. It is very important that you do not change the fingering, that is, keep using in the outline
exactly the same fingerings you will be using in the original version.
3. Finally a word about fingering. Bach rarely specified fingering. He certainly did not specify fingerings for this piece. So any fingerings you come across are editorial additions, in no way authoritative or binding. Treat them as well-meaning suggestions. Use them if they fit your physicality and make the playing of the passage easy. Otherwise,
change them. The only thing that can defeat the purpose of a piece of music is labouring under an inappropriate fingering (I myself use 234 on both hands throughout this passage, but 123 can be used as well). So choose the fingering that will allow
you the greatest ease and comfort in playing.
I hope this helps,
Best wishes,
Bernhard.