Hitchcocks Forum

Apologies if this has been covered before but has anyone fitted a new LED bulb to a pre focus 12v headlight?.

I have recently fitted our hosts "city light" bulb to my 2005 Electra X and I'm very impressed. Having last night ridden my 71 Bonneville in the dark with a bulb not much better than a candle I have seen the following link on eBay to an LED
https://www.ebay.co.uk/itm/LED-British- ... ect=mobile

Has anyone actually fitted an LED and if so any comments?

Thanks

Russ

I have used a couple of different H4 LEDs and they seem OK. But for convenience's sake you could easily replace the Bonnie's BPF headlamp unit with an H4 unit to take our host's fancy H4 halogen bulb. Our hosts sell Neolite units and Philips bulbs as a package, or you can get Autopal H4 units for about £14 if these don't suit. I'd avoid the Wipac Quadoptic on an old British bike or Indian Bullet.



The BPF bulb replacement you linked to is interesting (one of Paul Goff's?), it has the heat sink INSIDE the light unit, which is a plus point if your Bonnie has the flat back Lucas headlight shell. Most of the H4 LED replacements I have seen have a heat sink or even a fan at the back which can sometimes cause clearance issues.



I'm assuming you Bonnie's electrics are in otherwise good shape. What's the state of your current BPF headlight unit?



A.

Yup I popped a LED H4 replacement in I got from A well knows auction site in the UK and that works a treat.

I got an LED H4 from a place called classic car leds for my bullet. It's got a very compact heat-sink and the electronics are in a separate box but I still had to fit a wider inner headlamp rim to fit it in there without fouling the speedo. The lamp itself took a bit of tweaking to get the angle it sits in the backing plate right with a focused beam pattern (the angle is adjustable and really did need dialling in, the "set" angles are more of a guide as it turns out).



I have it in a neolite insert. Lighting is more than adequate once I got the angles correct. However, the reflector "cup" inside the neolite insert had fallen off and was rattling about in the bottom after less than 300 miles. I just cut it up with tin-snips and pull it out through the hole. Doesn't seem to do anything useful anyway.



So yes, LEDS can be good. As good as a filament bulb. I would say that the H4 one I fitted cost nearly twice as much as that ebay unit. They don't seem to do BPF bulbs on the site I got mine from though.



It's also worth checking what the voltage drop is between the battery and your bulb. It can be enormous with decades of corrosion on switches and terminals. I've seen an enormous difference made to bike lighting using just a can of contact cleaner, a bit of wet and dry paper and a can of silicone grease.

Oh yeah. Don't try to use one with direct lighting. There are stop and tails that will work with AC but headlamp ones give the light output of a small sun for a fraction of a second then pop.

Russ' Bonnie will have either a reg/rectifier or old type rectifier and zener diode keeping it all DC, most likely powered by a Lucas RM21 alternator, unless he has upgraded.



If someone wanted to use the LED H4 replacement on a Bullet with an AC headlight, replace the AC regulator with a Boyer Powerbox or similar.



A.