headlight lens query.

Following recent off road excursion one of the bits I'm looking for is standard 7/7.5 inch round headlamp. Puny on here has got one stashed away which c/w the old skool fresnel type lens - I think more recent machines have clear glass (or plastic depending on type of lamp). The original glass lens on mine is undamaged, what I'm trying to figure out is whether clear glass or marked (fresnel) type glass in a better bet.

So far advice had been conflicting...... my understanding is that the marked lenses focus the beam better, but clear gives a wider spread and allegedly passes more light.

A bit of a left field query - anyone?

[DJ123]

if you get the clear fronted one, don't you have to have a headlamp with reflector mirrors inside to reflect the light and create the beam pattern? where as the marked type uses the marks in the glass to refract the light into the beam pattern
that is if i haven't misunderstood what you've said

Ok, here goes...

Modern (Plain glass fronted) headlamps use a shaped reflector to focus the beam. The traditional (lined glass) is the lens to focus the beam and give the beam pattern.

Hope this helps

Rich

Ta gents, so far so good.

I think what it means is this: don't stick a clear lens over an old skool style headlamp with no shaped reflector..... or you'll just get an unfocussed flood of light, like a clear light bulb. When you think about it, the H4 bulb/lamp is black tipped, meaning you need a decent reflector back there. Which suggests to me that with H4s using the lined lens is probably not that efficient.

I was going to ask if you swapped from a modern, clear headlamp to a lined lens unit, and everything else was the same, which would give better illumination...... but if I'm right about the H4 scenario its all academic. Clear it is.

Does any of that make sense?

Originally Posted by saintnick

Ta gents, so far so good.

I think what it means is this: don't stick a clear lens over an old skool style headlamp with no shaped reflector..... or you'll just get an unfocussed flood of light, like a clear light bulb. When you think about it, the H4 bulb/lamp is black tipped, meaning you need a decent reflector back there. Which suggests to me that with H4s using the lined lens is probably not that efficient.

I was going to ask if you swapped from a modern, clear headlamp to a lined lens unit, and everything else was the same, which would give better illumination...... but if I'm right about the H4 scenario its all academic. Clear it is.

Does any of that make sense?

Uhh, nope...

Put it this way, I've got a rectangular old style Stanley H4 (100/60w) headlight on my kmx 125 which provides a far better light than the twin H4 on the SV. Neither of which are as good as my mate's NTV650 (Old style round headlamp) with a 60/55 Nightbreaker bulb.

Now I'm not saying don't mix technologies but if you do let me know how it turns out, ok?

Regards

Rich

so using an H4 in a lamp with a focussing lens and spherical reflector may be a better bet than than using the same H4 with a modern, standard set up (ie clear lens, shaped reflector)?



link to puney's shed find

Update.

As mentioned elsewhere, and as Rich implied, the lined lens option seems to be the best bet, for the simple reason that a glass lens and metal housing allow upgrading of the H4 without risk of meltdown.

Will report back once we've sourced it and and got it fitted. btw PM for Puny

[mister c]

I had a std SV round headlamp on mine when I bought it & thought that it was pants at night. At the time I had a CB500 Honda that had the standard fresnel headlamp, so thought I would swap it onto the SV to see if it was any better.
I haven't used the SV lamp since as the Honda one is far superior, better spread of beam & on high beam I can see where I'm going.

Originally Posted by mister c

At the time I had a CB500 Honda that had the standard fresnel headlamp, so thought I would swap it onto the SV to see if it was any better.
I haven't used the SV lamp since as the Honda one is far superior, better spread of beam & on high beam I can see where I'm going.

seems old skool glass lenses work really well with decent h4s

I believe you will find that different "lined" glass fronts go with specific reflectors and are matched, just swapping/mix and match is most unlikely to result in a better light or light pattern. Swapping for HID "bulbs"can also make for brighter but less focussed beam resulting is light scatter that annoys other drivers, as the light emitted from the HID is in a different place to the original, even small amounts can make huge differences to the light pattern.