head/taillight stopped working, brake light works (78 Puch Maxi)

1978 Puch Maxi

- only upgrades are a bullet pipe and high-flow air filter, rest is stock

I've been riding my Maxi for over a year now. Lights were working very well for a while, but would occasionally flicker... maybe like 1 out of every 100 rides... and then wouldn't give me any troubles for a while.

Well, I was riding around a few weeks ago at night and the lights started flickering again. This time, they went completely out and didn't come back on as they normally do. This happened while at WOT (~35mph) on a smooth road (no bumps). Seemed odd that they'd just go out like that without hitting a pothole or something...

So now, the headlight and the running tail light don't work, but my brake light and horn still work just fine.

Ok so I kinda suck at wiring, but I studied the wiring diagram and my Maxi. It's wired like the first diagram (stock). I looked for any loose or frayed wires, wiggled some of them around while the bike was running to see if I could get juice through the line... but I'll admit I'm not entirely sure what I'm doing.

Before I start doing something stupid, I figured I'd just post it here to see if anyone else has run into a similar problem with their Maxi. My suspicions are loose or bad wiring, or maybe the headlight burned out and that somehow prevents the running tail light from working... or something. Idk, whatcha think?

tl;dr: head/taillight stopped working, brake light works. Looking for advice.

Note: I did try the Search feature and also Google, but didn't seem to come up with anything helpful.

Re: head/taillight stopped working, brake light works (78 Puch Maxi)

Clean all your connections, the metal connectors oxidize over time. The most common problem is bad ground, especially between wire connector and frame. It needs to be a metal on metal connection with no paint.

Also check the bulbs!

Re: head/taillight stopped working, brake light works (78 Puch Maxi)

Good to know! If I do find oxidization on the metal connectors, is there a proper method to clean them? Can I just dremel the shit out of them with... like... a wire disc brush?

I did check the ground wire to be sure that was still connected properly right off the block (metal on metal) but I haven't looked very closely at the ground coming out of the headlight/speedo bulb. I'll check on this next.

I've got a spare bulb laying around that I can plug in to verify if the bulb is blown. Would I be correct in thinking that if the headlight bulb burns out, it would prevent the running tail light from working?

Re: head/taillight stopped working, brake light works (78 Puch Maxi)

You have a 30 year old bike, you have oxidization, for sure.

A dremal is overkill, sandpaper is fine, fine sand paper is better.

There is more then one ground, any place that is connect to the frame.

Usually you can visibly see if a bulb is broken by a break in the filament. You could also hook the bulb up to a 9volt.

If the head went the tail light probably did too, depends on how the bike is wired.

Re: head/taillight stopped working, brake light works (78 Puch Maxi)

Well, I've finally gotten around to checking on some of these things. Much to my surprise, the connections on the headlight and even the switch look super clean, no rust at all. Connections were tight, no frayed cables or anything like that. I disconnected all the wires, looked them over well, then re-connected them. All are clean and shiny.

However, I did find that the wires running under the rear fender were frayed. So I picked up some 14 gauge wire from a local hardware store and snipped out the frayed section of wire and spliced in a new wire, then tucked it back under the rear fender. I really thought this would fix it, but sadly I still have no lights. I can still fire it up with no issues, but oddly all 3 of my lights aren't working now (head, tail, brake).

I don't think I did a shit job splicing the cable, but I guess that might be an issue. I'm gonna try again and see if that helps.

Oh.. and I did look at the bulb. The filament appears to be in good order (not broken or loose)... but I think I might try a new bulb anyway in the off-chance that'll fix it.

Any other feedback on this?

Re: head/taillight stopped working, brake light works (78 Puch Maxi)

Overpriced Parts /

Check wire block/buss tighen screws and if that don't work then undo the screws and check each wire end

Re: head/taillight stopped working, brake light works (78 Puch Maxi)

I had glanced at the block to see if anything was visibly hanging off or anything looked frayed. But, I did not check to make sure they are all secured tight.... so I'll do that next. Thanks for the advice, Ken!

Re: head/taillight stopped working, brake light works (78 Puch Maxi)

anyone else have this EXACT same problem? and SOLVE it????? my head/taillights stopped working mysteriously, but the brake light still works. bulbs are good. checked/cleaned wires in harness. checked/cleaned grounds to the frame.

Re: head/taillight stopped working, brake light works (78 Puch Maxi)

after checking all of the wires and dismantling/cleaning the switch etc.....

bad headlight bulb, looked good but tested bad. taillight wont work unless headlight circuit is energized. what a dummy! TEST YER BULBS.

Re: head/taillight stopped working, brake light works (78 Puch Maxi)

Tigran Taschyan /

I have a similar problem now but all of the lights went out... I'll check my connections for oxidation first, good thing I ran into this post :)

Re: head/taillight stopped working, brake light works (78 Puch Maxi)

derek cuellar /

> Tigran Taschyan Wrote:

> -------------------------------------------------------

> I have a similar problem now but all of the lights went out... I'll

> check my connections for oxidation first, good thing I ran into this

> post :)

Same thing just happened to me last night. Ended up getting pulled over by the NYPD and they let me go ticket free, cuz I had my lady friend riding on the back.

Tried checking all the grounds and for oxidation this morning, as well as the light bulb. Everything seems fine. Could there be a problem in the flywheel?

(I have a minarelli v1 general and I'm running a super simple wiring setup)

Re: head/taillight stopped working, brake light works (78 Puch Maxi)

I'm having a similar problem. I put a new LED headlight in and it was working good. Sealed beam, 6V spec off of Amazon. I also put 6v LEDs in the back for tail and brakes. Seemed to be working fine. Then a few days later, I noticed the lights only came on with the switch in one position, not the other. Today went out, and headlight and tail-light are both non-functional. I can see a little blip of light go through the LED as I turn the switch on and off. Grounds to engine are clean and good. Nothing out of place on the little plastic junction block. Brake light and horn work, but only on the front brake. Rear brake does activate light. Mine is also a 78 Puch Maxi.

Re: head/taillight stopped working, brake light works (78 Puch Maxi)

> Lee Snover Wrote:

> -------------------------------------------------------

> I'm having a similar problem. I put a new LED headlight in and it was

> working good. Sealed beam, 6V spec off of Amazon. I also put 6v LEDs

> in the back for tail and brakes. Seemed to be working fine. Then a few

> days later, I noticed the lights only came on with the switch in one

> position, not the other. Today went out, and headlight and tail-light

> are both non-functional. I can see a little blip of light go through

> the LED as I turn the switch on and off. Grounds to engine are clean

> and good. Nothing out of place on the little plastic junction block.

> Brake light and horn work, but only on the front brake. Rear brake does

> activate light. Mine is also a 78 Puch Maxi.

You can't plug n play led lights on a Puch. The lighting coils are designed for specific wattag bulbs, and the taillight coil is only excited by the correct wattage headlight bulb installed. The only way to run led lights is to get rid of your good, reliable coils and switch to a rectified and regulated lighting coil system. They are cheap and unreliable.

Re: head/taillight stopped working, brake light works (78 Puch Maxi)

> Seth B Wrote:

> -------------------------------------------------------

> > Lee Snover Wrote:

>

> > -------------------------------------------------------

>

> > I'm having a similar problem. I put a new LED headlight in and it was

>

> > working good. Sealed beam, 6V spec off of Amazon. I also put 6v

> LEDs

>

> > in the back for tail and brakes. Seemed to be working fine. Then a few

>

> > days later, I noticed the lights only came on with the switch in one

>

> > position, not the other. Today went out, and headlight and

> tail-light

>

> > are both non-functional. I can see a little blip of light go through

>

> > the LED as I turn the switch on and off. Grounds to engine are clean

>

> > and good. Nothing out of place on the little plastic junction block.

>

> > Brake light and horn work, but only on the front brake. Rear brake

> does

>

> > activate light. Mine is also a 78 Puch Maxi.

>

> You can't plug n play led lights on a Puch. The lighting coils are

> designed for specific wattag bulbs, and the taillight coil is only

> excited by the correct wattage headlight bulb installed. The only way to

> run led lights is to get rid of your good, reliable coils and switch to

> a rectified and regulated lighting coil system. They are cheap and

> unreliable.

I'm figuring that out. My LED head light and tail light were toast. I put another LED in the back and the original headlamp in the front and they are working again. I figured a lower watt LED would be safe, but I guess not! Every time I try an "upgrade" it bites me. LOL. I guess will just have to leave it old school and augment with some lithium battery powered lights for safety.

Re: head/taillight stopped working, brake light works (78 Puch Maxi)

Richard Eberline /

Head Light is the large internal coil, 6 volts AC with the yellow wire.

Tail Light is a small internal coil, 6 volts AC with the Gray wire.

HL Bulb is 21 watts

TL bulb is 5 watts

A kitted bike makes the coils put out max. voltage. You can test with a multiimeter set on ac voltage. Make a small wire and install this in with the yellow wire. Using a set of jumpers with clips, connect red to yellow pig tail wire and red on your meter. Black clip to a known good frame ground and the black on your meter. Tape all exposed areas and connections. Go for a ride with WOT, you can glance at your meter to get voltage. Over 6.8 VAC will blow bulbs.

Re: head/taillight stopped working, brake light works (78 Puch Maxi)

Yes, not sure what is going on. The LED headlamp I got was recommended by another member. By specs on box it should handle up to 12volts. So, not sure how these would be getting toasted from voltage. You say these things are putting out AC voltage, not DC? Maybe that is part of the issue with these LEDs. Or could be it's cheap Chinese kaka and it just died because it was junk and then the over voltage took out the tail light.

I don't want to mess with this too much. If it's just easier to use old school bulbs and it will be reliable, I'll go back to those. I'm going to get a flashing battery powered rear light for safety, like used on bicycles. A brighter headlight would be nice, but don't really run these at night, so not a big deal in the scope of things.

My Puch is only hitting maybe 30mph at the moment, so it's not "kitted" per say.

Re: head/taillight stopped working, brake light works (78 Puch Maxi)

Yes, you are stock, not kitted. A kit is a aftermarket, often larger, cylinder and piston.

LED lights require clean, DC voltage. Your Puch generates dirty, AC voltage, not DC.

The stock setup works very well, but only if you use correct wattage 6vac bulbs.

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