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Quick wiring questions, front brake light switch

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pmtremblay
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Quick wiring questions, front brake light switch

Post by pmtremblay »

Is 16 gauge wire OK to use for a front brake light switch, running 6v to an LED tail/brake light?

Fortunately my bike has a later handlebar perch with the threaded hole for the switch, and the proper switch is readily available. I have 16 gauge on hand, but I've read that the 6v bikes preferred 14 or 12 gauge. I'm not sure if the lower draw of an LED negates that, or if I'm asking for problems.

For reference:
Switch: https://www.euromotoelectrics.com/produ ... tch662.htm
Bulb: https://vintagebeemerparts.com/new-vint ... 8-654-131/
Battery: https://www.bobsbmw.com/store/product/y ... r27-6-volt
Patrick in Virginia
'66 R27
'22 G310R

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wa1nca
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Re: Quick wiring questions, front brake light switch

Post by wa1nca »

How many amps can 16 gauge wire carry?
Why Wire Gauge Is Important
Wire Use Rated Ampacity Wire Gauge
Low-voltage lighting and lamp cords 10 amps 18-gauge
Extension cords (light-duty) 13 amps 16-gauge
Light fixtures, lamps, lighting circuits 15 amps 14-gauge

That is more than enough
16 gauge will carry 13 amps
Led bulb shown with both brake and tail light most likely would draw less than 1/4 amp

Tommy
Last edited by wa1nca on Thu Jun 23, 2022 5:43 pm, edited 1 time in total.
Tommy Byrnes
54 R51/3, 55 R50/Velorex 560 sidecar, 64 R27, 68 R69US, 75 R75/6
Ashfield, Ma
USA

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jwonder
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Re: Quick wiring questions, front brake light switch

Post by jwonder »

I love the wire calculator on the wirebarn.com website.

Go to: https://www.wirebarn.com/Wire-Calculator-_ep_41.html

Its great to know voltage loss over distance per wire gauge.
James Wonder
Vice President, Vintage BMW Motorcycle Owners
2022 BMW Friend Of the Marque
Long Island, New York

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Re: Quick wiring questions, front brake light switch

Post by pmtremblay »

Thanks Tommy and James, great to learn new things. It looks like I'm safe and then some using 16 gauge.
Patrick in Virginia
'66 R27
'22 G310R

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Re: Quick wiring questions, front brake light switch

Post by pmtremblay »

Just to finish this thread out in case anyone finds it through a search:

My R27 had a later right handlebar throttle and brake perch on it when I got it, with a threaded hole. I got a proper Endurolast front brake light switch, which threaded right in, and ran 16 gauge wire (16/2 wrapped and rated for up to 300° F) under the tank and connected straight to the rear brake light switch. It's not elegant, but it works.

I'll do something prettier some day, for now I feel much better knowing I have a bright LED brake light triggered by either brake.
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Patrick in Virginia
'66 R27
'22 G310R

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Re: Quick wiring questions, front brake light switch

Post by wa1nca »

R27 never had a front brake switch
I think your right hand perch must have come off a late US model and has 2 throttle holes for both cables
Only one being used and has a single cable boot as shown

Yea that wiring looks like hell

Someday you can fix it
get ride of that 16 gauge wire
run a small 2 wire cable from the brake switch into the headlight shell
connect one wire to terminal 15/54 (power on when key is down any position) on the key board
connect other wire out of headlight shell, under gas tank, and then to the battery box and connect it to the terminal that has the wire coming from the rear brake light switch and brake light so brake light will work when front or rear brake are being used

Tommy
Tommy Byrnes
54 R51/3, 55 R50/Velorex 560 sidecar, 64 R27, 68 R69US, 75 R75/6
Ashfield, Ma
USA

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