Twin Headlight

[Parson]

Why do manufacturer's make bikes with twin headlights, then only have 1 on (unless on beam)?

It looks sh!t.

Either light both, or make bikes with only 1 light.
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Then gsx650F - Now VFR800F

[zark]

i believe.... it's to satisfy lighting regulations in different countries.

I can't be bothered to google it or cite a source for you though
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CBT - Oct 13. Theory - July 14. Mod 1 & 2 - June 15.
Rides a Fazer like an idiot... Edit: Now ride a Fazer Thou...

[Parson]

Yeah, I thought it would be to satisfy some nanny state legislation.

Still looks sh!t though.
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Then gsx650F - Now VFR800F

[stinkwheel]

It's so you don't appear to be a distant car to someone waiting to pull out of a junction when it's dark.

A motorcycle with two small, close together headlights 100 yards away looks exactly like a car with two larger, further apart headlights half a mile away. Distance perception is almost non-existant with a brightly lit object directly approaching you in the dark (They just appear to get slowly larger).

With twin headlights, a car driver comes up to junction looks, sees car half a mile away, pulls out. BAM! "Sorry mate, didn't see you. Came out of nowhere innit?"

Hence only one on at a time. Many manufacturers are now stacking multiple headlights either vertically or making them in some way asymmetric.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[talkToTheHat]

Also better beam focussing a pair of projectors focussed completely differently gives you a great dip beam spread with a very definate that makes the beam easily aimed. A seporate main can then be a nice tight spot that puts light further down the road filling in the cutout from the dip with a bright section. It's easier to do this with two projector lenses and single filament bulb than the horrible compromise of a single h4 or a pair of h4 lights aimed similarly. With h4 bulbs you cant have a dip and a main on at the same time so main has to be less focussed.
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Bandit. does. everything.

[RhynoCZ]

I run dual headlights, H1/H3, and it is perfect. As Talktothehat says, the low beam is focused independently to the high beam. Plus it looks cool to run it on low beam, it's so: Suzuka 8h Mid-summer dream, when the low beam is off the center of the bike.

When I had single headlight, H4, I could either use low beam or high beam, never both at the same time. Which meant, if ran on high beam, I couldn't see much in the close range and vice versa. I'm quite sure no dual filament bulbs run both filaments at the same time, as it would make the bulb (effectively) a 110w bulb and the filaments wouldn't last long.
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'87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor

[Fizzer Thou]

[talkToTheHat]

On a twin h4 bike like boxeye fazer where only one light is used for dip, is the left dip lens set for riding on the left with a horizontal cut and a flick up to the left and the right dip lens set for riding on the right?
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Bandit. does. everything.

[Hahadumball]

wired both mine on the fazer so theyre on all the time
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Fin: no matter how much I look at It I can't understand what was going through my head, all I remember is going about 80 and redlining it to stop it seizing.
360 Deg... Five 1/4 turns. :- Teflon-Mike 18 Jan 2015

[Hahadumball]

[Polarbear]

My round eyed Stripple used both lights for high and low beams, as does my Trophy.

If stinkwheel is indeed correct about not looking like a car, it isn't taken on board by all manufacturers.
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Triumph Trophy Launch Edition

[Silver_Fox]

[chris-red]

[Silver_Fox]

Off topic but I'm thinking about a Speed Four. I know nothing about them other than the MCN review though...

[chris-red]

[Silver_Fox]

Thanks!

[chris-red]

What I'd say is if you want something to do a lot of miles and be a commuter get something else, Fazer or Hornet etc. I don't think the Speed Four is particularly unreliable but it isn't that common, while parts aren't hard to get I reckon one of the others will be easier to live with. If you are using it for a fun bike go for it, of 600's of the era I think it is the best in that regard.
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Well, you know what they say. If you want to save the world, you have to push a few old ladies down the stairs.
Skudd:- Perhaps she just thinks you are a window licker and is being nice just in case she becomes another Jill Dando.
WANTED:- Fujinon (Fuji) M42 (Screw on) lenses, let me know if you have anything.

[RhynoCZ]

[Silver_Fox]

[panrider_uk]

The Pan also has both lights on at the same time - for both dipped and main.

Personally I like having twice as much light when on dark country roads.
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Current bikes: Honda ST1100 Pan European. Moto Guzzi V85 TT Travel