I printed a new top cover for my Titan, and it worked like a charm. However, despite that, I have 2 remarks:
1) the original cover has a notch on the bottom where the hotend is locked into the titan. This notch is missing on the reproduction, for no apparent reason. It does function without it, as the filament guide will keep the hotend in place as well, however, it would be nice to have the notch too.
2) I would forgo the bearing on the hobbed bolt, in the cover. The bearing E3D puts in there is total crap, I have 3 titans and on all three this bearing failed. I would just make a hole big enough for the axle to fit, with some slight play.
In general, the hobbed bolt contraption is a huge design flaw on the titan, as one cannot tighten that screw. Tightening it leads to locking up the bolt.