H4 headlight conversion

[Minority]

I'm just in the process of doing an H4 conversion at the moment which is basically the same as Coaster's, (just a little more radical with the surgery on the old bulb holder ).
Apart from getting a better light, one of my objectives (I have a SIP speedo, hydraulic brake hose and indicators attached to the headset) was to get a little more room in the headset.

First thing was to check the focal lengths of the old BA20 bulb and the new H4 to ensure a half decent beam pattern with a standard reflector/headlamp glass. This worked out quite well by removing the metal collar from the old bulb holder (a CEV type) and modifying and the H4 bulb like this:





This is how it now looks mounted in the reflector assembly:



I sliced off the back end of the original bulb holder and used JB Weld to glue it to the back of the H4 connector, so I could use the original spring clip fixing:



And this is how it fits:



Fortunately I had a spare broken bulb holder to butcher and play with allowing me to return to standard if this setup causes any problems.
It should be noted that I have dispensed with the useless side/parking light so it might not pass the UK MOT.
I'm hoping that my SIL 12v stator/BGM regulator has enough grunt to power the 55/60w bulb, but at least I have a BGM LED rear light to give it a fighting chance.
Today is final assembly day so I should see if anything shorts/melts/blows up very soon!

[wack 63]

I've never had the sidelight checked at the MOT but to get the focal point /beam correct I took the headlight off the scoot and wired it up to a battery ,then moved the H4 bulb in and out 'till it gave a good beam on the shed wall.

[coaster]

I'm hoping that my SIL 12v stator/BGM regulator has enough grunt to power the 55/60w bulb, but at least I have a BGM LED rear light to give it a fighting chance.

Mine has coped fine with just a standard SIL stator in the past although I have since re-wound the lighting coils to help with charging the battery.

[vRSG60]

Well I've just finished adding an H4 to my GP. The only struggle I had was when the switch was on dipped beam both filaments lit up, albeit dimly. I found this was my fault. I connected Red to Red, Blue to Blue and Yellow to Yellow (as you would). Except that wasn't correct. I looked up the H4 connections and I'd wired the earth up to the dipped beam wire and vice versa.
I connected a battery to the loom and checked all the lights. My only concern is the rear LED. It lights when the headlight is on but is a lot dimmer than with the headlight off, the brake light is also very dim, there's not much difference between the 2.
With the headlight off it lights up OK, quite a bit brighter. I haven't had time to start the scoot and try it that way, it's kept in my kitchen and a bit of a faff to get it in and out.

[Minority]

Went out for my first night ride with the H4 conversion and was pleased with the result.
Given the limitations of the original reflector and glass I have a nice bright light with reasonable beam pattern and a proper dip/mainbeam differentiation.

[GT Guy]

I'm currently doing this on my GP. In my block connector the red is the earth - according to all diagrams I have seen. So I have the blue and yellow on the block connected to the blue and red wires from the switch. I have spliced a wire from the red (earth) wire on the block and I have been plugging this into the black terminals on the bulb holder. My only issue is what wire plugs into that red earth wire. I have been trying either one of the 2 blacks from switch/loom. I have no headlight - only a taillight. What am I doing wrong?

Sorry for being thick

[wack 63]

The bulb holder earth wire needs to go to a good earth on the headset not to any of the black wires, these are the feeds for the rear light and speedo bulb only.

[Donnie]

What he said

I've spent the afternoon doing this to my Series 2 and couldn't figure it out until I did as wack said above, in fact, I earthed it to the earth for the sidelight and it works great.

[wack 63]

I shall have to start charging

[Donnie]