Help me please

[b1lock]

This is a unusual request for this sight but you guys are really smart and I figure you can help me out. I scored a 75 Honda MR175 cheap and in decent shape. These are really nimble enduro bikes and come with headlight and tail light but no brake light. It just has a 6v magneto electrical system. I put a dual filament taillight on and wired a brake light switch from the headlight hot wire to the filament that wasn't the taillight. It lights up just fine but then burns out all the light bulbs! Yikes! Is there a way to fix this? Maybe a inline resistor?

[b.walker5]

Did the lights work okay before you put the brake light in ?

[b1lock]

help

yes. And with the brake light disconnected they work fine. It is definitely the brake light causing the problem.

[fredintoon]

This is a unusual request for this sight but you guys are really smart and I figure you can help me out. I scored a 75 Honda MR175 cheap and in decent shape. These are really nimble enduro bikes and come with headlight and tail light but no brake light. It just has a 6v magneto electrical system. I put a dual filament taillight on and wired a brake light switch from the headlight hot wire to the filament that wasn't the taillight. It lights up just fine but then burns out all the light bulbs! Yikes! Is there a way to fix this? Maybe a inline resistor?

Hi Bob,
try stealing the power off the rear light power supply wire instead.

[b.walker5]

Yeah, thats what i was thinking as well Fred. Not sure about the Honda's but some mags ive seen have a seperate lighting coil for the headlight, with tail and brake coming off thier own coil. Maybe the extra load on the headlight coil is causing a voltage surge... ?? JAT. or the brake circuit is wired incorrectly and causing a short..

[b1lock]

brake light help

Well I'm not sure whats up here. I run it off the tail light and it still blows tail lights. I rig a seperate light fixture with a single filament bulb and hook it up to the brake light switch everything is good to go! It's gotta be something to do with the double filament bulb or the bulb socket. Its a old lucas taillight but it looks okay and checks out with the ohmmeter. But at least now I have to rev it up to blow the bulb, so its definetly a step in the right direction. Thanks, Bob

[b1lock]

Thanks

It's pretty cool to be able to talk to guys from Sakatoon and New Zealand to get help. Makes you wonder how the Wright brothers ever did it!

[fredintoon]

Well I'm not sure whats up here. I run it off the tail light and it still blows tail lights. I rig a seperate light fixture with a single filament bulb and hook it up to the brake light switch everything is good to go! It's gotta be something to do with the double filament bulb or the bulb socket. Its a old lucas taillight but it looks okay and checks out with the ohmmeter. But at least now I have to rev it up to blow the bulb, so its definetly a step in the right direction. Thanks, Bob

Hi Bob,
back in the day, Villiers-engined bikes had a similar lighting system that had coils in the flywheel magneto that fed nasty pulsed ~6V AC straight to the lights.
Those bikes burned out tail lights for a pastime.
What worked was to fit a 12V tail light bulb. Kinda dim but they didn't blow.

[b1lock]

brake light.

Thanks Fred. I have a old Bultaco that runs all the lights thru a resistor, not even a rectifier. It too blows bulbs faster than I can buy em. I think I'll try the 12v bulb and see what happens. I don't plan on riding at night, I just want to keep the law at bay. Thanks again Bob