My student had a difficult time playing those trills evenly. I have to say that there are many shorter mordents in this invention which my student executed fine (it was probably the result of our long-term study of Baroque music in historical informed manner). But the long trills were still a problem.
If you play a similar piece on any keyboard instrument (including organ) - and there are many examples of long trills in Bach's music - my recommendation is to know exactly how many notes of the trill will fit in one eighth-note. Usually it's 2 or 3. Make sure you emphasize the beats so that you won't get lost with the trill. In the case of G major invention, I suggested 2 notes - basically the trill would be played in sixteenth-notes with a little bit of an accent on every other note.
This practice makes the performance look slightly automatic but for a lot of people who don't have a good hand coordination it is very helpful at the beginning.
After you get used to it, feel free to play it more musically and add more freedom.
Transposing Sequence in C Minor: i-iv64-ii42-i