Switching Tail lights

[scottyintex]

The R65 has a two bulb tail light. The R90/6 has a single bulb with dual elements tail light. Today I noticed the R65 tail light is about twice as big as the R90 tail light....and I just happen to have a spare R65 light. Bigger is better when it comes to lights at night. I was wondering if it is possible to switch?  Have any of you every switched from a single bulb tail light to a dual. Looks like it is a dimensional match as far as bolting on.... but the wiring..........Would be cool if I could make the switch and put the bigger light on the R90.

[Bob_Roller]

You need to confirm which wire is the brake light and tail light .

The R65 has a gray wire with a black spiral band for the tail light, the brake light is a green wire with a red spiral band .

I think BMW has used a standard for this , as my oilhead has the same wire colors, I was looking into adding more LED lights to the rear of the bike .

Motorrad Elektrik has a plug and play LED replacement for a single bulb installation, it's called Beacon 1.


http://www.motoelekt.com/lighting.htm

[wilcom]

Bigger is better when it comes to lights at night.

My biggest fear has always been being run over from behind. I just installed a Hyperlight which gives you two more bright running lights that flash brightly when you hit the brakes.

Haven't road tested yet, but will report back when I get back on the road

[wirewrkr]

the wiring is standard, that isn't going to be a problem.
The real problem MAY be that the fender is different for the larger taillight. All twinshock airheads received that same makeover with the intro to the 1979 models in August of 78.
At least here in the USA.

[Rob Valdez 79 R65]

I would imagine you will be able to make the switch with no problems - wiring wise.

And then you can buy and install a Beacon II (and the Hyperlites...).

[montmil]

Do remember your now wayward R65 used a smaller, low wattage tail light bulb to prevent melting the plastic tail light lens. Replacing it with a multibulb LED lamp will increase the brightness of the always on bulb without generating the heat damage.

Watch the UJMs in Marble Falls. You'll probably spot a tail light bracket that might be adaptable to the large BMW light unit and the rear fender profile of your new ride.

At Scotty's joint, nothing leaves stock. [smiley=beer.gif]

Monte

[Dizerens5]

The standard R65 tail light bulb is 5 watt but finding that a bit dim I replaced it with a 10 watt bulb, goes straight in, been there for a couple of years and no sign of any damage.

[tvrla]

No problems swapping tail lights - fenders are all the same.

[scottyintex]

Hot damn it worked....yehawwww...red neck engineering strikes again. Wirespokes was right the R65 and R90/6 rear fenders are one and the same. That sucker was a perfect fit...... from the butt end it looks just like a R65.  The purist must hate me. But if it makes it run better...safer...or better looking...go for it. That swap doubled the size of my tail light. I had already planned on going to a Beacon I...but a Beacon II is even better. I am heading down to the auto parts store right now to get a 10 watt bulb to go in...replace the 5 watt till I can order a Beacon II. Thanks Constellation. And ya know...I think I see some hyper lights in my future. Now I have this spare R90 tail light...need to look into putting it on the sidecar. Thanks guys! I bought a spare fuse just in case I blew one out..but didn't need it.

[Rob Valdez 79 R65]

Yep - that light will look great on your sidecar fender!

[wirewrkr]

No problems swapping tail lights - fenders are all the same.

Geez Terry, I thought we wuz friends!
Look again, they are not the same.
the flat "shelf" area where the taillight sits is deeper for the larger taillight, as from 79 models and on.
If your fender on the R90 is IDENTICAL in that way to the R65, then someone swapped out your rear fender once.
I never said it wouldn't work, just that there was adifference.
I think it's just that the difference is so subtle, you may not see it until they are next to each other.
If you need pictures to be convinced...................

[Lucky_Lou]

I would imagine you will be able to make the switch with no problems - wiring wise.

And then you can buy and install a Beacon II (and the Hyperlites...).

I cannot imagine the "Flashing" Hyperlites brake lights would be legal here in the UK.
Lou

[Rob Valdez 79 R65]

I cannot imagine the "Flashing" Hyperlites brake lights would be legal here in the UK.

Too bad - they are the "bee's knees"!

[Barry]

As far as I can make out Constellations 10W bulb idea is legal in the UK.

I don't think there would be too much loss of contrast with the 21W stop lamp either as stop lamps are deliberately overrun short life bulbs and therefore not just the 4 times brighter than a 5W tail lamp that you might imagine but more like 12 times brighter.

I found some figures that suggest a 5 W tail bulb emits approx. 35 lumens and a 21 watt stop lamp over 400 lumens.

Couldn't find a figure for a 10 watt bulb but I think it should be somewhat more than double the 35 lumen output of a 5W due to it being more efficient.

Even without getting into issues like overrunning the lumen output of standard incandescent bulbs is not linear with Watts as larger bulbs are more efficient i.e. they emit more lumens per Watt.  Best illustration of this effect that we are all familiar with is the old standard domestic light bulb sequence of 40W, 60 W, 100W and 150W. The ratings are not accidental. Each bulb in the sequence has approx. double the lumen output of the previous one.

[Bob_Roller]

If you do replace the tail light bulb, make sure it's the short type like the one that came out, if the bulb is too close to the plastic lens, it will melt it, as the light is on continuously whenever the bike is running .