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Makotosun

1975 Yamaha Enduro 175 6v to 12v conversion questions/confusions/problems

  • Yamahamadingdong
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Heyo.

I finally decided to scratch "riding a motorcycle" off my bucket list, and went the extremely sensible route and bought a 45 year old 1975 Yamaha Enduro 175 off someone. It's is nice shape really and only had 750 miles. The headlight bucket is about the worst of it.

Me being new to motorcycles, and riding, didn't realize that the seller's "it's street legal" statements weren't completely accurate.

My dumb ass thought the two reflectors next to the tail light were blinkers. They sure aren't! The tires aren't DOT either, but I fixed that already. Fortunately, there's a spark suppressor already.

I was excited and didn't really pay attention to those finer details. I've always been a fan of Yamaha bikes and was either after one of these, or an XT225/250. I found this first and it all seemed good to go. and it's a two-stroke so I can let everyone know I ride motorcycles (or cut the grass a lot) even when I'm not on it.

Anyway, the headlight died in it, probably because the battery died and I took it out, but rode the bike around and played with the switch and probably blew the bulb. I also needed to get working rear blinkers.

While hunting around, I couldn't find much in the way of 6V blinkers. I wanted the original chrome ones that look kind of like lollipops, but they are harder to find now it seems, and are pricey anyways.

A lot of the great stuff I found was LEDs, and 12v, so I ended up down that rabbit hole and decided I might as well swap over to 12v since I'm already going to be wiring things.

I found a nice LED headlight bulb that is supposed to be for a Harley, but it fit's in there with a little pushing.

I found some Kuryakyn Bullet shaped chrome LED blinkers that also act as brake/running lights and fit perfectly in the strut hole where the old original blinkers would have went. I don't feel like getting rear ended, so these seemed like the best option for adding more lighting than just the tail light. I believe I can just splice the wires to the other blinker wires, and then to the brake tail light wire, but wasn't sure what to do about the running light wire. Any ideas there?

I've swapped the gauge bulbs to 12v LEDs, and the front blinkers, and rear tail light.

but now I've gotten to the "ah crap" portions of this idea.

I was reading a guide online where someone converted a slightly newer Enduro over to 12v. I made some assumptions that it would be similar, but there are some differences.

They show a 12v blinker relay with 2 prongs. The one in my bike has 3 wires going to it, so I returned the relay I got for the 3 prong one. It looks like I will have to invent bullet to F2 connector ends to connect to the new relay. The old one used 2 male and 1 female bullet!. That shouldn't be a big deal.

they also suggest a 12v regulator/rectifier combo unit that comes out of a Honda Cub. I picked one up, and it seems like it should be OK minus needing to again do a little connector gymnastics to match up female/males without cutting any wires.

.... but as I have now discovered, the 1975 Enduro has no voltage regulator! Is this 100% correct, or is it just hidden in some secret place on the bike? The rectifier is right there under the tank and has easy F2 connectors so getting connected to the new unit should be cake. I plan to leave it mounted in there and will pop this new unit in and mount it elsewhere in case I want to switch back.

What do I do about the lack of an old regulator? Something I read said to basically splice a wire from the ignition coil into the rectifier, but I didn't want to go doing that without being sure.

I'm also worried now that switching to the 12v battery might have some other unintended side effects like exploding the LED headlight. I found two SLA batteries that fit in the little shelf where the old 6V one goes, and was looking forward to not having to deal with the spillable one since I was riding around in 35 degree Cleveland weather like an idiot, and the battery just kind of decides to not be a thing during those temperatures, but it suddenly wakes back up when it hits 45-50 degrees outside. (I bought a new 6V battery before going on this 12V adventure).

I did manage to attach a new horn as well. The damn grounding wire snapped after I soldered it on because it's so old. I spliced 12 gauge wire to it, directly to the horn. It's not very pretty, but it should be OK and is hidden once you mount the horn! At least the power wire didn't suffer the same fate, luckily.

ONE last question, again maybe due to me misunderstanding bikes. Shouldn't the gas petcock, if turned all the way clockwise where it points up at OFF make it so gas doesn't come out? The two screws holding the fuel tap on looked rusty and I didn't want to chance it, so I just popped the hose off the end thinking it was closed. It sure wasn't. I thought since the tank is so small and would be light, I didn't need to drain it and could just pop the hose off and carry the tank over to the table and leave it there for now.

Once this adventure is all sorted out, I will post some pictures. I put some bark busters hand guards on it also. I made sure to remove the old grips cleanly and pop new ones on so I didn't have to cut up original stuff. I am trying to save any of the stuff I remove and storing it in a box in case I ever want to go back. The damn throttle body screws stripped out because they're so old and rusty, but we got lucky and used a metal pipe over the handlebar, against the throttle body, with some very light hammer tapping to scoot the throttle over just a little bit as needed for the handguards

I plan to ride this thing around fairly regularly, so my main goal with switching over was to have better lighting and horn options so I minimize my chance of getting rear ended or T-Boned by some unaware driver.

I'm just hoping this all goes smoothly so I can get going again.

Sorry this post is very long. I hope I've made things clear! I searched around a little but didn't see anything exactly like this disaster I have started.. if I missed a post, let me know!
Last edit: 04 Apr 2020 18:50 by Yamahamadingdong. Reason: said regulator instead of rectifier when talking about splicing wires from the coil!
04 Apr 2020 18:42 #1

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I happen to be doing the exact thing you are doing right now to a 75' DT-250 and what iv decided to do is convert everything to 12-volt get a 12-volt rectifier and I'm going to rewind the lighting coil for 12-volts (should be 36 coils 5 layers of 18 gauge magwire ) and run off 12-volt I wish you luck on your electrical adventure.
Last edit: 04 Apr 2020 19:10 by EJRONAN.
04 Apr 2020 19:06 #2

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  • Yamahamadingdong
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Oof.

I might be stuck doing that now since I already did all this other stuff and am beyond the point of no return and can't return the blinkers or headlight!

are there alternatives to rewinding the lighting coil without a voltage regulator?? I am definitely not an expert in that.
04 Apr 2020 19:16 #3

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if your 6-volt lighting coil is good all you should have to do is replace the rectifier with a 12-volt one and it should work but if you don't replace the rectifier even if you do what I'm doing you will still only get 6 volts there are other solutions but this is what I'm doing there are a few videos on how to wind coils ill see if I cant dig up the vid explaining how to do 12-volt on a dt400
04 Apr 2020 19:22 #4

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also, give this post a good look if you haven't already it is explained pretty well here (yamahaclub.com/forums/topic/25945-dt-175-mx-12volt-conversion/)
04 Apr 2020 19:25 #5

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  • Yamahamadingdong
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That's the guide I have been following! The blinker relay is slightly different, and I have no regulator though, so things got a little different.

I wonder if a 12v LED headlight will work ok with just the rectifier swap out then? I don't want to blow a 130$ LED headlight up because of wiring issues, or if the battery dies.

I think that's how the old headlight blew out. It definitely worked when I looked at the bike, but I bought it at the end of fall. Once it got cold, on Thanksgiving, we went out to check it out and the light was dead. It was so cold out, my guess is it was cold, the battery lost it's juice, and the headlight got over-fed and died.
04 Apr 2020 19:33 #6

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I know I know the video is not in English but it's basically what I'm going to do ill see if I can't make up a wiring diagram for what is going on there and get some more specifics (
)
04 Apr 2020 19:50 #7

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Rectifier is just a diode on the old bikes... doesn't care at all about 6v or 12v.

If someone is using a more modern regulator/rectifier combo unit, then you'd obviously need one with a 12 volt regulator.
1963 YG1-T, 1965 MG1-T, Allstate 250, 1970 CT1b, 1971 R5, 1973 AT3MX, 1974 TS400L, 1975 RD350, 1976 DT175C, 1976 Husqvarna 250CR, 1981 DT175G, 1988 DT50, 1990 "Super" DT50, 1991 RT180, 2017 XT250
04 Apr 2020 19:51 #8

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ahh yes here it is another member posted his trials on this topic (www.yamaha-enduros.com/index.php/forums/...c-12-volt-conversion)
04 Apr 2020 19:52 #9

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  • Yamahamadingdong
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Does this mean I can leave the old rectifier as is, and just swap the flasher relay and use a 12V battery + lighting all around the bike, and not have to worry since I have no regulator?

Or am I misunderstanding?
04 Apr 2020 20:00 #10

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