In an effort to improve the headlight on my twin a few years ago I got a Halogen BPF bulb from from Paul but the filament spacing must have been wrong as if main beam was set right, dip was only just past the front wheel.
The reflector was a little battered so I fitted the reflector from a Honda CB250N with the Miller glass, this takes a P43T bulb and this gave a better light and beam pattern, Paul does an adaptor ring for this fitting to H4 so I bought one of these and tried 3 LED bulbs from a China, the first two were triangular when viewed from the front with LEDs on the three faces, 2 lit up for dip and all 3 for main but the dip beam cut off was too vague.
The third had 2 faces with LEDs on, one for dip and both for main and the beam pattern and dip cut off were excellent, great I thought, however I found the light too blue such that riding down a lane with dark tarmac and the sides in full leaf very little little showed up as the light was absorbed rather than reflected, conversely a reflective sign hundreds of yards away was so bright as to be blinding, so I have returned to conventional bulbs until I can find LED ones that are in a similar colour range to conventional bulbs.