DT 175 MX 12volt conversion

[NE0]

Here in UK and probably Europe, we have single Pilot bulbs, or parking bulbs INSIDE the headlamp shell.

They are small bulbs; larger than the dash bulbs but smaller than an indicator bulb. Rated about 10w.

The ignition switch enables the tail light and parking 'headlight' to be ON with the key removed.

I guess so other road users can see the 'parked' vehicle. Not really aimed at being left on for too long otherwise it will drain the battery. Often its part of the tail-light circuit.

[Airhead]

Here in UK and probably Europe, we have single Pilot bulbs, or parking bulbs INSIDE the headlamp shell.

They are small bulbs; larger than the dash bulbs but smaller than an indicator bulb. Rated about 10w.

The ignition switch enables the tail light and parking 'headlight' to be ON with the key removed.

I guess so other road users can see the 'parked' vehicle. Not really aimed at being left on for too long otherwise it will drain the battery. Often its part of the tail-light circuit.

and they are also on when the keyswitch it in the second position (lights on) and so if your headlamp fails you will still show a front light so you can be seen by others

[oisact]

Plus all my results are based on the fact I'm using the C90 regulator, which one are you using to get your results? you don't mention it. If you're testing with original 6v one then you won't get the same results.

Everything is stock, however, I really don't believe the voltage regulator is part of the headlight coil / circuit. I get up to 20V AC at my headlight socket - it's not being clipped. You said on your bike the headlight is not part of the battery circuit, so your headlight is not affected by the regulator either, is it? What voltages do you see directly at your headlight socket?

[NE0]

I'm off to work now and can't reply in much detail at the moment, but suffice to say...

You really need to get hold of a circuit diagram!

Remember, on a stock bike with everything connected I'd get 6v at the headlamp!... to run the 6v light bulb...... otherwise it would blow!

If I DISCONNECT the regulator and rectifier and take the voltage at the headlamp I'd get the voltages listed in Part3 The lighting coil

Let there be light….

Remember also the c90 regulator/rectifier is a combined unit and replaces BOTH of the disconnected Regulator and Rectifier mention in the text.

I'll post some circuit diagrams to explain further when I'm home , until then off to work...................going to be late now!

[NE0]

Ok back from work and I've done this for the MX taken from the circuit diagram,

I know i may have used the WRONG colours but you need to see where the wires go

This is the circuit used when the IGNITION is on POSITION 2

Within the ignition switch, brass parts internally connect the separate circuits to function as ONE.

If you take voltage readings for individual wires disconnected from this complete circuit you're reading will not reflect the end voltage. ie taking a voltage reading on the yellow wire in the headlight shell on its own the volts will be over 15volts at higher revs,

Not the best choice of colours I admit BUT does this help you understand whats connected?

Because to say "I really don't believe the voltage regulator is part of the headlight coil / circuit " without access to a circuit diagram is not the smartest statement I've read !

Regardless of it being USA your bike will not be dissimilar . Our haynes manuals has US diagrams.

Edited May 13, 2018 by NE0

[NE0]

Here's the simplified circuit diagram showing the connections via the ignition switch (colours corrected)

the ignition switch positions

1 = Engine RUN. Indicator, horn, brakelight active powered by the Battery.

Gen charges battery via Rectifier white wire. White wire connects to the Regulator which prevents Battery Frying!

2 = Engine RUN Indicator, horn brakelight active. taillight and Pilot ON. Powered by the Battery.

Gen white wire continues to charge Battery but is disconnected from the Regulator,

Plus Headlight circuit now active either dip or beam. Powered by the lighting coil in the Generator. Regulator Switched to Prevent bulbs blowing!

3= Engine OFF. tailight/pilot light ON (For Night parking)

This is for the UK models listed.

I will check the US circuit diagrams but its unlikely to be so different!

You will notice how the REGULATOR and RECTIFIER are wired and involved in the circuits whether the lights are ON or OFF.

[oisact]

Thank's for the additional info. In your wiring diagram, how do you know how the switches are wired internally? IE double pole double throw, etc. Did you determine that from an actual schematic?

[NE0]

The ignition switch block diagram part comes from the circuit diagram printed in the Haynes manual.

I've cut out all the chaff and simplified the rest for clarity.

It shows the internal configuaration of the switch. There are other diagrams which shows the internal arrangements of the handlebar switches and the larger diagram (above) even shows the plug connections.

I've looked at the circuit diagram for the US models DT125 and DT175 F G and H models and whilst the main switch on these machines doesn't have position1, the circuit on position 2 is identical to their diagrams.

ie the rectifier, regulator and headlight are all connected to the same principle above.

as I once said to a grateful friend I might not have a degree or diploma......... but I can read a circuit diagram!

[nydamon]

Hello,

Greetings from an XT500 enthusiast from the US who is looking to go 12V! I have two questions regarding this mod. One is if the original lighting/charging coil on the DT is wound such that it has a white wire on one end, is grounded on the other end and the yellow wire is just a center tap between the white and ground?

Second, the SH570-12 is a 1/2 wave regulator/rectifier... correct?

Thanks!

[teledan]

I am in the middle of doing this conversion on my US 81 XT500. I am using LED turn signals and I thought that the stock flasher might work but it turns out it wont so I am waiting on a new flasher but everything seems to be working other than that. I am also running a capacitor in place of the battery. Oh and I did have an issue with the little indicator bulb in the gauge. With that in, all four turn signals would come on at once. I just pulled the bulb and it is fine now but I may end up doing this fix:

https://docs.google.com/file/d/0B0BD_MkiU7JpcHZHRnhCbXZGV2c/edit

http://www.rexs-speedshop.com/epages/es143131.sf/en_GB/?ObjectPath=/Shops/es143131/Products/ITK1

BIG thank you to the OP for all the work you have done on this! This is a great mod that should save me a lot of time and hassle! I will be doing it on the wife's XT250 as well!

[nydamon]

teledan, What bulbs did you use for the turn signals and where did you get them? I tried these and wasn't impressed even at night so I sent them back

http://www.superbrightleds.com/moreinfo/tail-brake-turn/1156-led-bulb-single-intensity-24-led/813/

[teledan]

I bought some cheap crappy ones on ebay. I don't like them and wouldn't recommend them. They are not very bright and one of them has some LEDs that are out. They look good just sitting there though!

I am still trying to figure out the flasher though I am wondering if there is something else going on with my wiring because they will not flash (and are barely on at all) while idling but they come on and start flashing when the revs get higher. I am getting a different flasher anyway so I will see if that helps. I am also going to borrow a multi-meter tonight and do some checks.

[NE0]

hi guys thanks for feedback, nice to hear this old post is still going strong and helping people.

To nydamon

is if the original lighting/charging coil on the DT is wound such that it has a white wire on one end, is grounded on the other end and the yellow wire is just a center tap between the white and ground

Whilst i've never stripped a DT lighting coil down ,I have always understood them to be two wires over one core. One was a full winding, the other a half winding, with both sharing the same ground.

regarding the regulator/rectifier, I couldn't tell you if its half wave or not, you would need to search the web for the answer there, sorry don't know!

To teledan,

if your signal turns are not bright check the wiring especially the earth, but first I'd connect them directly to the battery , bypassing everything, and see if they work as expected. Process of elimination yes, but check basic function first. You will need a multimeter for sure. good luck with that one.

Great to know another bike has had a "neo conversion!!"

[nydamon]

Neo this is working well on my 79 XT500 so far. Thanks for the write-up. I checked the wiring diagrams, the DT175 and US XT500 (at least until 79) have the same AC/DC lighting/charging coil layout: one coil with a center tap.. Since we are using the white and yellow wires, the regulator has to be half wave. A full wave wouldn't work with the coil grounded to the stator.

I just finished riding some unlit areas with a Candlepower 35/35W H4. It was OK (not sure if it was better than the 6v) but I'll try a 60/55W tomorrow night.

PS Teledan, I know a guy on the west coast that can fix that tank of yours. http://www.joeabbatescycletherapy.com/ It will not be cheap but it will be beautiful. He did the tank on my garage queen.

[teledan]

Thanks for the link, that dent really bothers be I was actually just thinking about grounding the signals straight to the battery so thanks for reassuring me! The turn signals actually aren't that bad at higher rpms ( above about 2.5k )

[NE0]

Nydamon,

Earlier I posted

I use a 12v 45w/45w bulb same design as the 6v one with the 3 holes in the flange from good ol' ebay. Look for APF Bulb 12v 45/45w

its a lot brighter than the 35w, and its at maximum brightness above 3500revs.

Not saying it lights up the whole street but an improvement all the same.

I find this bulb quite alright for city riding, my lights are on day and night, unlit roads are ok, providing the revs are kept up, as you slow to a stop then a candle might be better!!! but otherwise I've not had any problem. Its not a searchlight, but you can see quite clearly where you are going.

The best bit is the availability of 12v parts, brighter brake and turn signals and a good sounding horn!

and for those thaat may not be so sure....I can convert it ALL back to 6v without having cut a single wire! no harm done!

I blew my first tail light bulb yesterday,! it lasted from march 2011 until now doing over 2000 miles.

I also charged the battery for the first time but only because I wanted to give it a boost, no other reason, i.e it wasn't flat! The conversion works fine for me.

[nydamon]

Just came back from a short ride in the woods with a bit of unlit paved roads. The 60/55W H4 is pretty dim under 2000 rpm but beyond that it's a real winner. I love the low beam which is a nice bright wide rectangular patch straight ahead of you. I actually like the high beam pattern on the 35/35W HS1 better since there is not so much unlit space between the illuminated pavement just in front of you and the road far ahead of you; there is sort of a horizontal unlit space straight ahead of you with the 60/55W...if that makes sense. I figure it's manufacturer dependent. The 35/35 was a Candlepower but it said GE on the bulb. The 60/55 was marked Candlepower. I'm very happy with this mod and appreciate the time and effort everyone, especially NEO, has put into sharing it.

And I concur...not one cut wire...and thanks to ebay it cost under $90: $60 of which was the H4 housing, bulb, battery and a superbrightled.com motorcycle LED tail light.

[teledan]

Yeah, my headlight is about the same, under 2k rpms and it is not very bright. I am using a 60/55w bulb as well. Are you running turn signals? If so, how are they working for you?

[nydamon]

All of my bulbs except the tail light are incandescent. I have the stock signal housings. I also have two extra sets of stock rear signals. One set is new and one is used. PM me if you like.

[teledan]

Thanks for the offer but I still have my stock signals. I don't like how big they are so I got the small LED signals. Do the stock signals work well for you with this conversion?