//ArrowChat Code

Upcoming Events for the Next 120 Day(s)

Results 1 to 5 of 5

Thread: 83 yt125 need some help with lights

  1. #1
    Join Date
    Aug 2018
    Location
    Michigan,USA
    --
    12

    83 yt125 need some help with lights

    So my yt125 lights are pretty bad. Was wondering how I would go about upgrading to LEDs if possible, or if it isn't worth the trouble and stick with what I got ( even though it sucks)

    Sent from my SM-J727U using Tapatalk

  2. #2
    Join Date
    Jun 2009
    Location
    Leander TX
    --
    2,158
    Buy a cheap one, plug it in, and see what happens.

    Might need to add a 2- wire regulator. Might need to convert to DC.

    We just had a good LED thread (I'm pretty sure 185s and YT125 wiring systems are very similar):
    http://www.3wheelerworld.com/showthr...t-Ideas-needed

    There are a few others, too.

  3. #3
    Join Date
    Apr 2012
    Location
    MI, USA
    --
    2,321
    I don't have a perfect collection on the Yamaha 3 wheelers for service manuals, and that's one of the machines I'm missing. I'm guessing the YTM175 is a similar machine so I'll base my info on that (could be wrong). Well The Yamaha diagram gives less info about the stator/alternator sadly, but it seems like it has a common ground which makes things a little trickier and you'll need a multi meter to validate a few things.

    The Yellow/Red wire is the AC power for lighting, but the second wire isn't used in the harness (grounds though engine, aka common ground system), need to check the Black wire at the engine to see if it's a frame ground (runs to the CDI). The machine does not have a voltage regulator or rectifier, so bare min you'll need a voltage regulator on the Yellow/Red wire and frame ground (possibly that black wire from the engine). The LED power supplies are designed for DC power generally, so it's best to run a voltage regulator + rectifier (generally the same part), but in your case you have two options if you want to run one.

    half way rectifier (2 wire basically a diode, need a voltage regulator separate most likely) - just simple run it between the engine yellow/red wire and the harness yellow/red wire, all the light plugs would be switched to half wave dc power. Might have more flickering at idle, and I'm not sure, but you might loose total power output from the alternator since only half the power is usable.

    full wave rectifiers generally have a voltage regulator build into them. This is the trickier one to use, it takes AC in, and outputs full wave rectified DC (not pure DC btw). However the DC ground/negitive cannot touch frame ground because the AC system uses that already. If any lights use frame ground, you'd have to disconnect them from that, and also the ring terminal on the harness that goes to a bolt. You'd have to hook up the rectified DC power to the Yellow/Red wire (positive) and Black (negitive) once the Black wire is isolated from the frame grounds.

    In your case, probably easiest to just run the LED on AC power and risk it going bad. Just add in a voltage regulator to be sure. Also what ever size the headlight is, don't go over that for the LED light or the system wont' have enough juice to power it up.

    Here's a couple of wire diagrams on the YT175. I used the top one to base my info on.

    FYI, just a new stock headlight bulb might brighten it up more than you'd think, might be worth a shot if the bulb is old (they get dim with age), or maybe someone put in too high wattage of a bulb in the headlight. I didn't see an alternator spec so not sure what the limits are, guessing it's 35w or 45w.

    Oh, FYI, note that sometimes wires change colors. Seems common on Yamaha's. Aka, Yellow/Red wire at the engine becomes Yellow at the headlight, and Blue (L) at the tail light, and Gray at the Oil warning light. The Tri-Z does the same thing in it's harness and confused the hell out of me until I took the harness warping off.



    Last edited by ps2fixer; 11-25-2018 at 10:28 AM.

  4. #4
    Join Date
    Aug 2018
    Location
    Michigan,USA
    --
    12
    Quote Originally Posted by ps2fixer View Post
    I don't have a perfect collection on the Yamaha 3 wheelers for service manuals, and that's one of the machines I'm missing. I'm guessing the YTM175 is a similar machine so I'll base my info on that (could be wrong). Well The Yamaha diagram gives less info about the stator/alternator sadly, but it seems like it has a common ground which makes things a little trickier and you'll need a multi meter to validate a few things.

    The Yellow/Red wire is the AC power for lighting, but the second wire isn't used in the harness (grounds though engine, aka common ground system), need to check the Black wire at the engine to see if it's a frame ground (runs to the CDI). The machine does not have a voltage regulator or rectifier, so bare min you'll need a voltage regulator on the Yellow/Red wire and frame ground (possibly that black wire from the engine). The LED power supplies are designed for DC power generally, so it's best to run a voltage regulator + rectifier (generally the same part), but in your case you have two options if you want to run one.

    half way rectifier (2 wire basically a diode, need a voltage regulator separate most likely) - just simple run it between the engine yellow/red wire and the harness yellow/red wire, all the light plugs would be switched to half wave dc power. Might have more flickering at idle, and I'm not sure, but you might loose total power output from the alternator since only half the power is usable.

    full wave rectifiers generally have a voltage regulator build into them. This is the trickier one to use, it takes AC in, and outputs full wave rectified DC (not pure DC btw). However the DC ground/negitive cannot touch frame ground because the AC system uses that already. If any lights use frame ground, you'd have to disconnect them from that, and also the ring terminal on the harness that goes to a bolt. You'd have to hook up the rectified DC power to the Yellow/Red wire (positive) and Black (negitive) once the Black wire is isolated from the frame grounds.

    In your case, probably easiest to just run the LED on AC power and risk it going bad. Just add in a voltage regulator to be sure. Also what ever size the headlight is, don't go over that for the LED light or the system wont' have enough juice to power it up.

    Here's a couple of wire diagrams on the YT175. I used the top one to base my info on.

    FYI, just a new stock headlight bulb might brighten it up more than you'd think, might be worth a shot if the bulb is old (they get dim with age), or maybe someone put in too high wattage of a bulb in the headlight. I didn't see an alternator spec so not sure what the limits are, guessing it's 35w or 45w.

    Oh, FYI, note that sometimes wires change colors. Seems common on Yamaha's. Aka, Yellow/Red wire at the engine becomes Yellow at the headlight, and Blue (L) at the tail light, and Gray at the Oil warning light. The Tri-Z does the same thing in it's harness and confused the hell out of me until I took the harness warping off.



    Yeah, the wire that was supposed yellow red is yellow. Confused the heck out of me, thought someone was messing with the harness. Thanks for the info, I'll check the stock set up out. If I can roll with that no sense in messing with it.

    Sent from my SM-J727U using Tapatalk

  5. #5
    Join Date
    Apr 2012
    Location
    MI, USA
    --
    2,321
    Yea no clue why Yamaha thought that was a good idea, I hope they changed since then. Haven't worked on anything newer than 85 for the Yamaha harnesses. Have a 99 warrior, but never touched the wiring on it.

    Anyway, got a little more time now, I'll dig into the headlight bulb size and such. Alright... so this machine throws another monkey wrench into things. It's a 6v system instead of the most common 12v for today's machines. Bulb is reasonable priced at the Yamaha dealership though, part number 527-84114-09-XX. It's 25w/25w so the alternator in it must only be like 35-40w total. 25w isn't a whole lot, but if someone put a 12v bulb in, it will be extremely dim. The LED idea might be the only option to get good lighting. Could get a small LED light bar like a 4in or something (24w most likely) and see if you can get it spaced out right to bolt up to the stock headlight bolts. Looks like the headlight bucket might be a spot where the wire has a ton of connections, might loose that special feature sadly (shielding from the weather/being visible).

    https://www.partzilla.com/product/ya...76f020dab101da

    Also, the wire diagram above is accurate for your machine too, same part number for both machines.

//ArrowChat Integreation Code //