lights operation on mini 50K1

I have a question about lights on a 50K1. I hooked up all new wiring, key switch and battery. Should the lights come on when key is switched on or does the engine need to be running for the lights to work. Thanks!
 

Mini K1

Member
Hey Larry,

With a battery in the circuit of your K1, the lights should illuminate when the key is on the second position (3-position switch).

The brake light switches are wired such that they will always illuminate the taillight, even with the ignition off and key removed, assuming the battery is connected to the electrical system.

All other Mini Trails (no battery), the engine would need to be running for the lights to illuminate.
 

Mini K1

Member
I had the same issue when the frame was repainted and everything was reassembled... no lights. Poor ground on the ignition switch to frame mounting was the culprit. Check the headlight/taillight grounds too.
 

kirrbby

Well-Known Member
I thought the tail and brake lights would work with the key on, not running...but the motor had to be running to have the headlight and high beam indicator.
 

Mini K1

Member
Well, I just reacquainted myself with my Z50A, K1. With a charged battery connected in the circuit and the ignition switch in the second position, the headlight and high beam indicator will illuminate with the engine not operating. Without a battery in the circuit, the engine must be operating for all lights to operate. Also, strangely enough, both brake light switches will illuminate the brake light (battery connected in circuit) with the ignition key in your pocket.

Here's the wiring diagram for the Z50A, K1.
 

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Well......I scraped paint at the frame mount for the switch and no change. Even went as far as to try the old switch mounted on the frame but no lights. Used a volt meter and checked the two wires(brown & green) of the harness that connect to the tail light pigtail but no power there. Disconnected the harness bulkhead connector from the switch and checked for voltage between the harness red and blue wire spades in the connector and have power to volt meter there. Connected the harness back to the switch and thinking what else. There must to be a ground problem, just gotta find it. For comparison, here's a pic of the headlight wires. The repro light on the left, the original on the right. The ground wire on the original connects at the ring, while the repro is from the tab at the back of the bulb socket. Grounding problem maybe?
 

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Mini K1

Member
Well, that's frustrating. Using some jumpers with alligator clips, connect one end to the headlight shell and another lead to the metal taillight assembly and the other lead ends to a fastener or good ground on the bike, like the coil bracket. With a good ground, (and good bulbs) you should see lights. The repo headlight should not be an issue.

I troubleshoot backwards; starting with where you are seeing voltage and keep moving until there is none. Sounds like you're doing that.

Keep us posted Larry, for we're all curious too.
 
ok, among other distractions during the day, I had a break to get back to tackle the problem. I did some grinding to remove paint from frame/bracket surfaces to make a good ground contact. Turn the key to 2nd position, still no illumination from the tail-light. So then I tried an experiment and ran a jumper from mounting bolts of the frame and the taillight housing as shown in the pics. Doing that, the Tail light works, as well as the brake light. I did notice that if I jiggled the ignition switch housing within the frame mount, that there was a difference in brightness of the bulb so more attention to full contact of the switch to the frame is needed. Meanwhile, when the ground jumper is removed.....no light. Puzzled as to what to do......as the jumper should not be an integral link of the wiring scheme in order for the light to work. Would the housing gasket pose a problem of not getting a good ground? I'm sure there's hundreds of these reproduction parts used in restorations with no issues.
 

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Mini K1

Member
Kudos to you for your persistent troubleshooting. The taillight gasket is a great insulator, no doubt. Looking at the wiring (headlight/taillight) on my K1, I noticed and now recall installing a ground wire for both the headlight and taillight, that is concealed in the new wiring harness. I used the coil mounting bracket for both runs. Technically, the lighting should operate without this mod, but the additional grounding bond made for a more reliable and easy fix for reliable lighting. Unfortunately, the headlight brightness is about the equivalent of a 2 D-cell flashlight.

I also recall having contact issues within the original ignition switch as well and went with a reproduction switch. Nowadays, they sell them with Honda keys. https://chpmotorsports.com/shop/electrical/ignition-switch-with-honda-keys-included/
 

kirrbby

Well-Known Member
You need good, metal-to-metal connections...
engine to frame
coil to frame
key switch to frame
hl bucket to fork/frame
tl bracket to frame
tl housing to tl bracket...via the mounting bolts.
You should be able to test for continuity with a tester...touching engine...to everything else.
 

Mini K1

Member
What Kirrby said is paramount, for the Z50A K1 wiring harness itself has no dedicated grounds. I have a CL100, K0 (original owner) and it has several ground lugs built-in the harness at various locations.
 
I have the switch from CHP. I swapped out original and new during testing. Neither of them solved the problem. That's when I started experimenting. Guess I will get started on scraping the paint at ALL frame contact points like Kirby describes. I really hope this corrects the problems. Running ground wires just doesn't seem like this should be normal given the number of restorations done on these bikes.
 

OLD CT

Well-Known Member
I know you are working on a z50 but, a small 5 inch or so green taillight ground wire is the norm right from Honda, for a CT70. It goes from the taillight bracket bolt to the frame.
 

Gary

Well-Known Member
I'm with old ct on this but only because your using an aftermarket taillight. When I get a chance I'll take the lens off mine and see how it originally looks
 
well after a number of hours with "diagnostics" and problem solving, I finally have a grounded electrical system. Ran a separate ground conductor connected within the taillight housing and over to the frame/bracket mounting. Scraped the paint off of both mating surfaces and connected the ring terminal, now I have lighting! Did the paint scraping at the key switch and that solved the "flickering" problem too. Thanks for everyone's input on the topic, it was a big help! Now I can sleep tonight......zzzzzzz.
 

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Gary

Well-Known Member
I see you "fixed" your problem but there is the reason why it did not work- the aftermarket taillight does not have the socket ground like the original ones do. But then I see the new OEM ones are different as well,probably a combination of that and paint between the light unit mounting and the licence plate bracket and then that to the frame.

taillight ground.png
 
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