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TOPIC: 1975 yamaha DT 250 has a dull (dangerous) headlight

1975 yamaha DT 250 has a dull (dangerous) headlight 14 Mar 2019 18:45 #1

  • mpritch41
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Went riding on My 1975 yamaha Dt 250 a few nights ago...could barely see because the headlight was so dim. I bought this used and really had not ridden it at night...I don't know if the electrics were messed with.
Anyway, any ideas this side of a 12 volt system to brighten things up?

Thanks

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1975 yamaha DT 250 has a dull (dangerous) headlight 14 Mar 2019 20:11 #2

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mpritch41 wrote: Went riding on My 1975 yamaha Dt 250 a few nights ago...could barely see because the headlight was so dim. I bought this used and really had not ridden it at night...I don't know if the electrics were messed with.
Anyway, any ideas this side of a 12 volt system to brighten things up?

Thanks


Outside of a halogen helmet light or converting to CDI or 12 volts no.

a

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MINIBIKESERVICE@AOL.COM 1971 125cc AT1-C (DOROTHEA) 1971 175cc CT1-C (BRANDY) 1970 250cc DT1-C (MONICA) 1973 100cc Hodaka Combat Rat (ABBY NORMAL) 1975 DT400 (BONNIE BELL)

1975 yamaha DT 250 has a dull (dangerous) headlight 14 Mar 2019 21:45 #3

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With a magneto driven headlight the higher the wattage the weaker the light. We had replaceable bulbs here in nz so anything was liable to happen when owner had changed the bulb. in saying 'that' your model might've had a 35/35 sealed unit or bulb type anyway & was the highest wattage available so system was designed for 'that'. So my guess is someone has fitted a 12 volt headlight & it hasn't got the grunt to run it--have a look & report back please. Other option is if a voltage regulator is fitted then maybe it's crook or on the other hand once again if a 12volt headlight fitted then the original yamy 6 volt regulator will stop it 'even trying' to make it bright. We had magneto powered tail lights on ours so if someone had fitted a 12volt in the rear it would affect the headlight, even instrument bulbs would make a minor difference downhill. So check headlight first & so long as the battery is in circuit & full of water etc then try disconnecting the regulator if you can find it. It'll have one yellow wire if original & might be somewhere near the air filter box or below it--guessing. If ya brave after that you could unhook the battery but take revs up slowly because if its putting out good voltage it'll blow the headlight with high reves plus instrument bulbs & tail if mag powered. I know i'm repeating myself but on my RT1 360 ride to work bike i had an XJ600 headlight with a high wattage quarts halogen bulb. No battery, just head & tail light & the mag put out enough power to damn near melt the tar seal but at revs its max voltage was what the bulb could stand & never blew.
Sorry, that was just a bit of useless info thinking back 40 years lol. Was a 'big' headlight & looked mean. Had an underneath RD350LC pipe too modified at the header to fit & was nice & quiet & gave it more grunt too. Think i cut the footrest cross bar off for that to get it up close to the crankcase. Anyway---.

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1975 yamaha DT 250 has a dull (dangerous) headlight 15 Mar 2019 01:59 #4

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mpritch41 wrote: Went riding on My 1975 yamaha Dt 250 a few nights ago...could barely see because the headlight was so dim. I bought this used and really had not ridden it at night...I don't know if the electrics were messed with.
Anyway, any ideas this side of a 12 volt system to brighten things up?

Thanks


To be honest, even the 12v stock headlights of that era were crap, which is why Cibie conversions were so popular.

My DT360A and RT2 won't be ridden at night (if and when I ever get them on the road!).

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