NC50 wiring question-please help

have (2) 1978 NC50`s,just started working on them,both are wired differently,one with a battery,one without,is there a sc ematic somewhere for these,did the spring repair on one turns over good but no fire,do the lights need to be good on these?thanks in advance

Re: NC50 wiring question-please help

update ...have good sparkon the one with no battery,found a schematic on "the other site"looks like my battery is backwards

Re: NC50 wiring question-please help

Jonas Quimby /

You do NOT want to run an Express without a battery. No battery/dead battery will cause your lightbulbs to blow. And those headlights are expensive.

Re: NC50 wiring question-please help

If you are going to run it without a battery disconnect all but the black wire coming off the magneto, the connectors are located by the intake manifold. but the best advice is to get a battery and everything should work fine.

Re: NC50 wiring question-please help

Thanks,but it`s probably too late,was wired that way and probably running when the starter spring broke,it`ll just have to be a daytime cruiser

Re: NC50 wiring question-please help

Leon Swarmer /

or you can fix it right so you can cruise day and night.


NC50 wiring question-please help


i have a running NC50, with no battery or extra lights or anything (and its not clear to me that it ever had them) .. the headlight and tailing work fine, _but_, when the brakes are applied, rather than having a brighter taillight, both the headlight and taillight shut off.. doesnt kill the engine or anything though, just the lights.

is this indicative of:

- blown lights (is there another bulb in the taillight? i didnt look)

- creative wiring (given that there's no battery, and also the starter turnkey has been removed)

- points/magneto/condensor issue? the guy apparently replaced the condensor right before i got it, but perhaps he botched something

i have the schematics from the manual, but im not real well versed in electrical stuff as yet (can kinda read circuit diagrams, but not sure how to troubleshoot them)


Re: NC50 wiring question-please help

bumpity bump

Re: NC50 wiring question-please help

Leon Swarmer /

Whew, You have a can of worms there.

The tail/brake light bulb should be a dual filament.

It appears that when you squeeze the brake handle you are giving the head/tail light a ground.

It's amazing you still have a headlight.. the bike was set up to run with a battery. The battery acts as a voltage regulator.

Without it most expresses send too much voltage to the headlight and blow that $30.00 lamp.

prolly not an issue with points etc. since it is running.

Re: NC50 wiring question-please help

should i just disconnect the brakelight cables from the brake levers, then?

maybe it does have the battery and i just didnt notice it.

Re: NC50 wiring question-please help

Leon Swarmer /

The battery should be under the seat. undo the thumb screw and wiggle the seat. it lifts off.

You could test with with the brake light switches disconncected, but if you ride it on the street you will want a brake light.

Re: NC50 wiring question-please help

under the seat is the condenser, right? is the battery under that?

i do want a brakelight, but moreso i want the head and taillight to not go out when the brakes are applied, i think, as it did get the attention of some cops...

er which circles back to the original question, why would this be happening?

does "It appears that when you squeeze the brake handle you are giving the head/tail light a ground." imply that im shorting it to the frame or somesuch somewhere along the way?

Re: NC50 wiring question-please help

I would suspect three possibilities.

1. The battery is shot and because it's still in circuit, it's allowing the additional and bigger load of the brake light to pull the system down. Check the battery.

2. Someone messed with the wiring and you'll need to untangle it. The best way to do this is to take the brake light bulb out and see if pulling the break lever still pulls down the headlight. If not (meaning the headlight doesnt go out), the brake light bulb may be the wrong type or the filament may be shorted. Keep in mind that the best way to diagnose electrical problems it to disconnect everything and reconnect one thing at a time untill you get the same failure.

3. These scooters have an allternator that makes juice for the scooter to run on, to power the headlight and to recharge the battery. These coils don't normally fail but it can happen. Once you've eliminated the other possibilities you'll have to test the out-put of this with a meter while it's running.

You will find your issue in 1 or 2. I'm 99% sure.


Re: NC50 wiring question-please help

Leon Swarmer /

Hmm not remembering where the condnesor is, but the battery is directly under the seat. I've heard taht there may be a rubber flap over it, but I've never seen one on the 4 I've owned.

make sure your brake/tail bulb is 6 volt and that the filaments aren't touching or that the wiring in the socket isn't touching/

Mike had good thoughts.

« Go to Topics — end of thread

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account