peugeot tail lights/ignition

On some mopeds the tail light is essential to run the ignition system. Is this the case with a peugeot? One of the 2 filaments in my tail light is burnt out. I don't know if it's the brakes or the tail light.

I've had trouble getting my ped to run reliably. I'm wondering if I have some electrical issues. Is there any way to check the coils without some kind of inductance meter? Anyone know what the DC resistance should be?

Compression is 130 psi. Muffler and exhaust port are clear (even running without the muffler doesn't help much). Timing is set according to the timing procedure posted by (i think) matt wilson. I have some kind of spark, because the thing runs, but only after much and hard pedalling, and even then, it often dies. points/condenser and plug are all new.

I will check the spark tonight or tomorrow. I do this be holding the plug against a ground right? How can I tell if the spark is weak or not? Assuming it is good, the only thing left to look at is the carb, right?

I will get it running good someday soon... he he


Re: peugeot tail lights/ignition

Hi Geoff:

The easiest way to make sure you're getting a good spark is:


<li>Get someone to "help" you.</li>

<li>Remove the spark plug from the bike and insert it into the spark plug boot.</li>

<li>Ask your helper to hold the spark plug by the threads.</li>

<li>Start pedaling.</li>

<li>Ask your helper to "check if the cylinder head is vibrating".</li>


<b>How to interpret results:</b>

If your helper shrugs and says "it isn't vibrating very much", you aren't getting a good spark.

If your helper shrieks in pain and punches you in the spleen then your spark is plenty good.


Re: peugeot tail lights/ignition

On my 1978 103 the tail light was sperate form the ignition circuit. The tail light did not need to work for the moped to run.

Measure the coil with a DC ohm meter, it should be roughly 0-15 Ohms. If the coil is defective (unlikely) the resistance will be very great or infinite because the wire is broken in a spot. Coils are just a long wire wound up so they very likely go bad.

If you go back to fred's guide there are 3 things needed for an engine to run:

1. Compression

2. Spark

3. Gas

You know that your compression is good.

Check for spark like chris suggested. If you don't have spark review the manual scan that I've posted. Also look at the schematic I've attatched.

If you do have spark then the problem is with fuel flow.

Also when you put the new condensor in, did you do a job job of soldering the connection?

Re: peugeot tail lights/ignition

>Also when you put the new condensor in, did you do a job

> job of soldering the connection?

Don't know about a job job, but I do think I did a good job... :-) Doesn't look like a cold solder joint as far as I can tell. I don't have a capacitance meter to really check, though.

I can't open the file you attached, and I can't save it either...

maybe you could send it to Thanks.

And which coil measures 0-15 Ohms? The primary, secondary, or the one by the taillight? None of the three coils are open, but they could still be shorted out and measure a low resistance instead of an open, which would also be a failure.



Re: peugeot tail lights/ignition


I misposted the attatchment. You should be able to view it now.

I'll get back to you other questions later


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Re: Why I Love BOB


This is kind of "Off Topic" for the thread you posted to. I guess that's true to the "Subgenius Spirit". but.... it could be considered "Hi-Jacking" a thread.

This would have fit right in in the "Controversial Topics" thread...

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Not a real big deal, Lib, but the board has had a lot of 'attacks' reccently.... the more polite the better.

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Re: peugeot tail lights/ignition

The pic above shows a more detailed schematic of the Peugot ignition. I'm not sure if this is the same ignition on your ped. The schematic shows that the ignition coil primary is grounded through the brake light bulb and brake switches. You can remove the brake light bulb and start your ped and then apply the brakes. If it stalls, then you have the ignition in the schematic.

The ignition can have problems even is the brake light bulb is good if any of the connections are bad. The ignition coil primary current has to flow to the brake light bulb and then all the way back to the magneto ground for the ignition to work properly when the brakes are applied. If a connection is bad, the engine would not run well or would stall when the brakes are applied.

Any connection that feed the brake light bulb need to be clean. The contacts of the bulb socket need to be clean. Also, the ground of the brake bulb may return to the magneto ground via the frame of the bike. If it does, this can be a problem on an old bike were there is rust between joints. To ensure a good ground, it would be good to run a ground wire from the brake light bulb ground back to the magneto ground.

To test the brake light switches, you can test how the engine runs with the brake light bulb removed and with the brakes not applied. In this case, the ignition coil primary is grounded through the two brake light switches in series. If either or both switches are not closing properly, then the ignition current will be interrupted. The engine could run rough or stall when the brakes are not applied and the bulb removed. You could also test the switches with an ohmmeter.

With a brake light bulb installed, if the switches are faulty, you would also see the brake light coming on when the brakes are not applied.

There is also a rectifier in the ignition for RF noise reduction. If it were open or short it might make the engine run rough or stall.


Re: peugeot tail lights/ignition

For the Peugot 103, the ignition specs are:

timing: 1.5mm BTDC

point gap: 0.016 in.

plug gap: 0.016 in.

Re: peugeot tail lights/ignition

Thanks for that diagram, paul. I don't know if it's the same as my ped, is that from a 103? I will probably have time to check it out this weekend or next week. Now that I have some schemtics it will be easier for me to troubleshoot things.



Re: peugeot tail lights/ignition

The schematic appears to be the same as the one that Matt posted, only it shows what is inside the boxes. I assume Matt's jpg was for the 103. The book I got it from only said Peugot.


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