1980 Honda Express NC50 wiring questions

I am having a problem with my rear turn signals and brake light. The brake light lights up, but it doesn't get any brighter when the brakes are pulled. I am pretty sure I am wiring it right but I could be wrong. Also I have another question about the turn signals. They work but the right ones will blink and the left one just lights up. When I have the right one on some times the brake blinks with it. I don't know if they are supposed to blink or just be on. If anyone can help me out that would be great. I have been looking online for a wiring diagram for a 1980 but the only one I can find is for a 1978 and those don't have the turn signals so it is wired differently. Thanks for the help.

Re: 1980 Honda Express NC50 wiring questions

Adam Kollipara /

Here is a 1980 Honda Express NC50 Wiring Diagram (pg. 29-10).

Here is the rest of the 1977 - 1981 Honda Express Shop Manual.

If the brake light blinks a little bit with the signals, that's normal (my 1981 NC50 does the same), because it's a 6V system, and it doesn't have that much power. Urban Expresses and Express SRs had 12V systems later on in 1981-83.

You might want to get some halogen turn signals (very bright), a 12V car taillight (works perfectly and easy to find, and I think the one I have is a 1157 taillight), and a removable headlight bulb assembly (not sealed beam) if you don't have one already. No special bulbs are needed for the signal and high beam indicators, and the speedo, just the generic ones (look for the number on the bulb).

Also, if you don't have a new battery, get one. If you don't have a good battery, you can blow the headlight and the other lights won't work right. If the fuse is damaged, got a new one. The battery is the regulator, so if it is weak or dead, there is nothing to regulate the amount of power going to the lights, which means they get surges of power way greater than 6V and blow out. And lastly, make sure all the wire connectors are in securely. My turn signals and ignition switch wires came out at one time, causing them not to work.

I hope this helps quite a bit!

~Adam

Re: 1980 Honda Express NC50 wiring questions

Ya that helps me out. I have also noticed the relay thing under the seat will make the turn signal blink if I hit it. I don't know if that needs a new one or if that is what it is supposed to do. I am new to this and it has been sitting for 10 years or so. Its nice to get some help and get it all ready. I will get new bulbs and put them in. Do you happen to know where or what size of an air filter to get for it? I want to add a new one to help it.

Re: 1980 Honda Express NC50 wiring questions

Adam Kollipara /

I would say get a new flasher. My grandpa found an old Volvo 6V flasher can in his barn. Works and fits perfectly, and you can hear the flasher clicking while the engine's running. Probably something like this flasher would work. But you'll have to find out which two prongs make the lights flash. Pretty much any flasher can that's 6V would work.

Do you have the stock airbox, aftermarket air filter, or none?

~Adam

Re: 1980 Honda Express NC50 wiring questions

I have a stock one. I want to put on an aftermarket one to add a little bit to it. I think it would help it run a little better. Sorry anther question to go back to the brake light. I still am not sure how to make it light up brighter when I pull the brakes. I have it wired correctly from what I can see on that diagram. It is a little hard to see which wires connect to each other. They are a little fuzzy.

Re: 1980 Honda Express NC50 wiring questions

You should get the 6 Volt tail light bulb, thats what is supposed to be there. Your blinkers wont continuously blink if you just have the key on. The engine should be running and charging the battery. You will notice as your driving the blinkers will work just fine. I have 3 NC50s a 78, 80 and 81. I had to bring them all back from the dead, and all of them had wiring issues I had to deal with. They all work perfectly now after many head scratching nights. I will also reccommend the replaceable headlight bulb option a previous poster mentioned, well worth it. ALL the bulbs should be in and working so you dont blow the bulbs one by one. I have a very cheap alternative for the little instument bulbs too if you need them, just let me know. Oh yea, I got the 6 volt 1157s from NAPA. ? Go figure.

Re: 1980 Honda Express NC50 wiring questions

NAPA sells 6V 1157s??? How did I now know this?

Re: 1980 Honda Express NC50 wiring questions

Yo! I made a video of the turn signal wiring on my Express. Mine is a 78, but wired like a 1980 with 4 signals. The first post of mine in that thread has a color coded wiring diagram that may also help you. Are you using a 4 amp hour battery? Be sure to check that. The turn signals on my bike DO blink when it is idling, and the whole system is 6V. A weak battery could cause them to stay on solid, and might make your tail light not come on 'bright' when you brake as well. Also, I had a problem just this week with the signals on the left side not blinking. It turned out that one of the little plug-in connections near the tail was loose. Plugged 'er in all the way, and BAM. Blinking again. Good luck to you! Here's a LINK to the wiring video.

Re: 1980 Honda Express NC50 wiring questions

I gave you some misinformation about the rear taillight..NAPA sell a 6V 1154 bulb not a 1157. "Wagner" is the manufacturer. Its the same as a 1157 in looks but its the 6V flavor. The instrument bulbs are A-62 for the blinker and speedo backlight, and A-1262 for the Highbeam indicator, I got those from 1000bulbs.com and they were very very inexpensive. EIKO is the Manufacturer.

Re: 1980 Honda Express NC50 wiring questions

Sorry I should have said all this already, but I replaced the battery with a brand new one when I cleaned everything out and got it running. Also I had to buy a new headlight and ring off eBay. The person who I bought it from already changed it to be able to remove the bulb. I am still confused about the whole brake light problem. I watched the video which helped and made sense about the wiring. I might try a new relay. Nothing on this bike has been changed since it was made.

Re: 1980 Honda Express NC50 wiring questions

Hey man, the green wire with the yellow stripe is for the brake light. I would trace it forward from the tail light as far as you can. Also, make sure you have the correct bulb back there. It's kind of a special bulb that does three things (tail light, brake light, flashes with signals). Should be a 6V 32/3 CP. I would check the filaments too to make sure one is not blown. Another possibility is dirty contacts in the switches inside the brake levers on the handlebars and work the brake levers. Get some quick-dry electrical cleaner at your local auto parts store and squirt it in there. Squirt some into the turn signal switch while you are at it. Hope this helps.

Re: 1980 Honda Express NC50 wiring questions

What exactly do you mean inside the brake levers on the handle bars. Where exactly are those at? Can you tell me what the other colors do for the brake light? I tried to unplug them and they didn't work when I unplugged the green one. I think that is the ground wire, but I'm not 100% sure.

Re: 1980 Honda Express NC50 wiring questions

Adam Kollipara /

Yeah the original wiring diagram isn't very clear. I know that Mel posted a thread about adding turn signals on a 78, and had a color wiring diagram. Pretty sure the colors are the same because Mel used a 1980 wiring harness. It's possible that your wiring harness is damaged somewhere, maybe, maybe not.

As for the air filter, if you want a new stock one, look on eBay or cut one out of a sponge and soak in motor oil. If you want an aftermarket one (seems like you do) you can get some small air filter from treats. I think the carb intake diameter is 24mm, about an inch.

~Adam

Re: 1980 Honda Express NC50 wiring questions

Adam Kollipara /

I think what Mel is talking about is a little black button type thing behind the brake lever. If you pull the left/right brake levers back, and look behind it near the brake cable, you'll see a little black plastic button. When the brake lever is not pulled, the button is pressed in, not allowing the brake light of the taillight to illuminate. When the brake lever is pulled, the button is not pressed in, causing the brake light of the taillight to illuminate. I attached some pictures of the button: a close up, one from underneath, and one from the side farther away. Maybe yours is stuck in, not allowing it to get bright when pulling the lever. Check this on both levers.

~Adam

Brake Lever Close.JPG
Brake Lever Underneath.JPG
Brake Lever Side.JPG

Re: 1980 Honda Express NC50 wiring questions

Brown supplies power to the tail light. Green is ground. Orange and lite blue are the left and right turn signals (tells them to blink) and run from the turn signal switch on the handlebars to the turn signals. And, like I said, green and yellow wire is for the brake light. You should be able to track this down. Make sure all your connections are clean and tight.

Re: 1980 Honda Express NC50 wiring questions

Sounds good I really appreciate all your help! It has been very helpful! Has anyone ever put on an aftermarket air filter? If you have I am wondering which works best or if it is even worth it.

Re: 1980 Honda Express NC50 wiring questions

It looks like I will be changing air filters. My rings failed this week, so I decided that while I had the cylinder and head off, I would go ahead and order the 70 cc DR kit. I will be using a bigger carb with a bigger jet, and will need a better exhaust and air filter too. I've been playing around with trying to make my own. I want one that I can wash out because there is lots of dust and dirt roads where I live. Also want it to be small so it won't be in the way. I'll post a photo when I get 'er done... could be next week sometime.

Re: 1980 Honda Express NC50 wiring questions

Adam Kollipara /

In the attached pic, this is the air filter that was on my Express when I bought it. It's a K&N metal mesh air filter. My advice is that you get one that has a foam outer filter and not a metal mesh thing like this, because you can clean the foam ones way easier. Now I have an original 1981 NC50 airbox.

~Adam

1981 Honda Express K & N Air Filter.jpg

Re: 1980 Honda Express NC50 wiring questions

so hold up guys, there's just gonna be an extra wire in the back just dangling there?

Re: 1980 Honda Express NC50 wiring questions

i found the craziest thing at home depot...a lawnmower generic aircleaner you know the ones that have the long screw that goes in carb hole on lawnmowers. Anyway its almost dead on dimensions as stock box. Would have to some engineering but its a foam filter...only issue as it's 100% enclosed I dont know what to do as far as air input....cut some grooves? big circle hole?

Great Information

Merle Schlotfeld /

Just wanted to say thanks to everyone for all the wonderful information on Honda Express. I got mine a few weeks ago. I love it but I can see I have much to learn about keeping it in top shape.

Re: 1980 Honda Express NC50 wiring questions

Jack Rutherford /
nc50lawn.jpg

Briggs & Stratton air filter

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