Throwing Light the Right Way - Left.

Well, six (6) years of MOT's on the KLR650, and this year the nice MOT man told me it has a foreign headlight and so the dipped beam casts light the wrong way (i.e. to the right and it should be to the left). I should have known this because I'd looked at the headlight several times for the appropriate UK biased 'E' markings and they are not there. I simply developed wilful blindness to the fact and seen has no-one has mentioned it before...

Anyway, first step e-bay. Nothing doing, it's all crap. Knackered looking parts (existing headlight is actually nice apart from it's recently discovered fatal flaw) and the pictures on there don't show those all important markings without which they may well be as bad as the one I have. It would take more energy than I can summon to start asking difficult questions of the denizens. 

And obviously I'm not going to buy one new of Kawasaki. Do it yourself time.

First thing is looking at the pattern in the headlight glass. Normally you can see a pattern of striations which guides the light for the dipped beam to one side or the other. The old-fashioned way of fixing this was simply to tape over that pattern to get it through the MOT. Except there is none on this headlight. The pattern is plain. Which is actually a good thing, because there's not a lot an enthusiastic bodger can do about patterns cast in glass.

Next, take the whole stupid thing apart. Front plastics off (4 bolts) 2 small bolts at the bottom adjuster and two big bolts either side of the headlight, pull out the wires and... PAYDIRT!

 

Back of my headlight showing the H4 Bulb canted off at an angle of 10 degrees

The H4 bulb is offset in the headlamp reflector at an angle of 10 degrees to the right (the difference between the red and blue lines on the picture) by the tabs on the bulb fitting into slots in the reflector. 

Here's an interesting fact - I have always assumed that the "dip shield" in a H4 bulb, which shades one side of the low beam filament, blocked the light from going to the side. Which turns out to be bollocks - it actually blocks the light from going down. So the above works because the arrangement casts all of it's light onto the top of the reflector at an angle off to the right and then from the reflector downwards to the road - and further still to the right. No light goes onto the bottom of the reflector which would cast light skyward. Which all sort of makes sense otherwise the H4 bulbs would need to be marked for left hand drive or right hand drive and they are not. Who would have guessed.

All that leads up to the very simple fix for this - extend the slots in the metal reflector so that the bulb can rotate 10 degrees to the left instead. File/hacksaw/dremmel and 10 minutes work.