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Hi everyone and merry chrimbo to all. 

Ive pretty much finished my resto project and everything’s great apart from the dim lights. I bought the bike with the problem, and thought it would be an easy fix. Nothing seems to fix the fault. So far, I’ve replaced the whole wiring harness, the rear light and wires, brake light switch and wires, front light holder and wires, speedo cable and wires. All 6v bulbs and I even had the light coils checked and replaced. So everything has been done apart from the handlebar switchgear. 

I had the frame powdercoated, but sanded the main earth point for the harnsess, so it’s a good earth. Even, ground two points of the five engine mounting points away hoping that might help. 

All the electrics work like they should including the pass light, just dim lights. 

Has anyone had this problem? Does the engine need to be grounded at every point? I thought if the engine had one good ground that would be enough. 

Really at a loss with this, and if I can’t sort I have to admit defeat and had it over to an auto electrician ?

 

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 Pretty sure the Pe is one of those bikes that has lights,but they are only there so they could show a headlight and taillight at the end of the enduro as per 1980 ish rules.

  The lighting coil puts out more power as the revs increase,but since there is no rectifier the lights are powered by AC volts and not much above 6v at the best.

  If you want better lights,probably contact a company like Rexs Speed shop in the Uk.They can wind you are more powerful lighting coil and provide a rectifier to get a steady 7.2 volts at a lower RPM...or maybe even a 12v conversion.

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You should also check the total wattage you are drawing. A voltmetere on the AC circuit will give you a good idea. Max voltage on these bikes was close to 9V at full throttle, idles was about 4.5V. (Volts X Amps=Watts) It is a fine line between low wattage (brightest possible) bulbs and bulbs failing at high rpm due to the lack of load and a voltage regulator. Over voltage on these bikes was managed by total wattage. If one bulb fails, the other tend to fail right after unless the faulty bulb is replaced. Concurrently, if you mistakenly put in a higher than spec'd bulb, the others on the same circuit will also be dimmer. Though as others have said, the lights on DS bikes back in the day were not so much to let you see where you are going as to let others see you when you fall.....

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21 hours ago, nsman said:

 Pretty sure the Pe is one of those bikes that has lights,but they are only there so they could show a headlight and taillight at the end of the enduro as per 1980 ish rules.

  The lighting coil puts out more power as the revs increase,but since there is no rectifier the lights are powered by AC volts and not much above 6v at the best.

  If you want better lights,probably contact a company like Rexs Speed shop in the Uk.They can wind you are more powerful lighting coil and provide a rectifier to get a steady 7.2 volts at a lower RPM...or maybe even a 12v conversion.

 

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Thanks nsman,

I always remember my old it was dim, but nothing like this. I had the coins rewound by West Country but if I can get the coils upped in power all the better. Thanks for great the lead (wish I posted here first) I dont think I’d get through on the current mot regs with the lights as is.?

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2 minutes ago, Waz Hoare said:

Thanks nsman,

I always remember my old it was dim, but nothing like this. I had the coins rewound by West Country but if I can get the coils upped in power all the better. Thanks for great the lead (wish I posted here first) I dont think I’d get through on the current mot regs with the lights as is.?

Changing the winding rarely makes much of a difference. The magnets in the flywheel are what makes the power (along with the engine spinning it of course).

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24 minutes ago, William1 said:

You should also check the total wattage you are drawing. A voltmetere on the AC circuit will give you a good idea. Max voltage on these bikes was close to 18V at full throttle, idles was about 11V. (Volts X Amps=Watts) It is a fine line between low wattage (brightest possible) bulbs and bulbs failing at high rpm due to the lack of load and a voltage regulator. Over voltage on these bikes was managed by total wattage. If one bulb fails, the other tend to fail right after unless the faulty bulb is replaced. Concurrently, if you mistakenly put in a higher than spec'd bulb, the others on the same circuit will also be dimmer. Though as others have said, the lights on DS bikes back in the day were not so much to let you see where you are going as to let others see you when you fall.....

Thanks william1, 

i only had a basic light tester, so never checked any outputs. Just assumed it was earth, then coils and finally out of desperation replaced the harness. Even took removed all the paint away from the engine mounting points last night. And still nothing. Upside, everything looks nice. Unfortunately couldn’t find the correct bulbs, but managed to find the equivalent in listed in the owners handbook. I’ll get a voltage meter tomorrow.... that or a big bin to put it in?

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22 minutes ago, Waz Hoare said:

Thanks william1, 

i only had a basic light tester, so never checked any outputs. Just assumed it was earth, then coils and finally out of desperation replaced the harness. Even took removed all the paint away from the engine mounting points last night. And still nothing. Upside, everything looks nice. Unfortunately couldn’t find the correct bulbs, but managed to find the equivalent in listed in the owners handbook. I’ll get a voltage meter tomorrow.... that or a big bin to put it in?

Bad grounds are 99% of the time the issue with these simple systems though the bad ground typically manifests itself as causing lights to prematurely burn out, not be too dim.

I am not at all familiar with the stator in your bike. I have seen some of these simple systems that only have two coils, one for ignition, one for lights with a blank space or two where other coils 'could' be. If that is the case, you could put in more coil(s) and effectively doubling the output. Some too, convert to 12V and have had better performance. Same wattage bulbs, just 12V instead of 6V (draw is 1/2 the amps, less load on the wiring to boot!).

The bike is gorgeous, by the way, nice resto!

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1 hour ago, William1 said:

Bad grounds are 99% of the time the issue with these simple systems though the bad ground typically manifests itself as causing lights to prematurely burn out, not be too dim.

I am not at all familiar with the stator in your bike. I have seen some of these simple systems that only have two coils, one for ignition, one for lights with a blank space or two where other coils 'could' be. If that is the case, you could put in more coil(s) and effectively doubling the output. Some too, convert to 12V and have had better performance. Same wattage bulbs, just 12V instead of 6V (draw is 1/2 the amps, less load on the wiring to boot!).

The bike is gorgeous, by the way, nice resto!

Thanks William1, 

i was pretty crap with electrics? thanks for the great advice and glad you liked the resto too. 

All these old crosser and enduro bikes were so cool back in day and still deserve saving, as long as their ridden in anger and don’t end up as a garage queen ?

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Hi all, 

Meant to post this ages ago.

Got to the bottom of the problem, with the help of an auto electrician and it was just a lowly bulb. It was a fake.... I know it I should have checked it, but assumed it was actually 6v

For anyone with a light problem they just cant work... check the voltage of the bulbs and wattage is correct! I spent a dogs age trying to find a fault in the system and it turned out to be a fake lightbulb (7.1v) that I bought off ebay. Sadly, all the 6v bulbs now are really poor quality as theyre all made pretty much in China and voltage varies bulb to bulb. In the end I managed to find nos bulbs, and it cured the problem with the help of a regulator. Can now drop down the gears without blowing bulbs

On the upside I now have a spanking new harness, switchgear, lights, both lighting coils, and I even had an inline regulator made to combat the spikes, as the later models didn't come with it for some reason. 

So if anyone stumbles upon this with dim or blowing bulbs... check that the bulbs are what they say they are first. It'll save you a bucket load of money and time :D 

 

Hope this helps anyone who finds it

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