Hey everyone,

I picked up 1978 DT400E that I'm currently rewiring, but I've run into a bit of confusion with the outputs on the stator.

In a nutshell, all of the electrical components I'm using are stock, but much of the harness was bastardized to the point where I've begun to make my own from scratch. I've got the stock Mitsubishi CDI unit hooked up to the stator and other ignition components so that the bike is able to run, but the issue I'm facing now involves the wiring diagram in the manual. According to the manual, I'm supposed to connect the white/green wire to the rectifier diode, but I wasn't able to get spark unless I connected it to the white/green lead on the CDI box. What's interesting is that I still have two unused leads coming from the stator, a green and a green/red which aren't mentioned at all in the manual. After poking around a bit online (Thanks, previous posts!,) I believe that these leads are the coil responsible for the headlight, but I couldn't find any official documentation to support it. I was hoping that someone here might be able to shed some light on this situation, can I use this output for the rectifier? and If so, how would it be wired?

Thanks for reading, and for any advice you might have!

I can't remember ever seeing "white/green" as anything but a CDI color...  Yamaha tended to use the same/similar color codes for many years and models. 

The order of the colors matters.  The first color is the main wire coior and and the second color is the stripe.  GREEN as the main wire color is used for battery charging. 

Since you have two "greens" you might have an ignition from an earlier model?  Or it might not be a US model?  There might be numbers on the stator and flywheel that can ID what you have. 

Green/red would be the color used to charge the battery and you'd just leave the solid green disconnected...  I think that's how the 1976 (twinshock) was wired. Monoshocks had only the Green/White. 

Oh, and you must wire it with a voltage regulator if using one green.  Earlier bikes that used two greens did not have a voltage regulator and relied entirely on "balancing" the stator output against the load to keep the voltage within range.

"I can't remember ever seeing "white/green" as anything but a CDI color...  Yamaha tended to use the same/similar color codes for many years and models." 

Not that it helps (sorry!), but white/green is also the colour of one of the wires coming from the speedo for the self cancelling indicators on the RD400 and others.

Don't dwell on what i say & MarkT will have it sussed.
But i'm guessing a bit that maybe there's a diode in the cdi box & they were referring to that with white/green but nothing to do with charging.
I'm only used to pure white going to the rectifier for charging but i'm thinking charging gets its source to the white via green [or green/red if connected] via switching.
If you have a white/green then you must have white/red also which are retard & advance for the cdi pulser coil.
I'd have thought there's a yellow there too for the lights & has highest output.
Is your wiring diagram in a genuine yamy manual or an aftermarket repair manual.

I looked up the Yamaha 1976 DT400C wiring diagram and it DOES show a "green/white" to the CDI box in the diagram.  It also has the Green/Red and solid green shown.

So you may have an ignition from a DT400C?  Either that or have you verified you have a 1978 DT400 by looking up the VIN number in the tables?  (Registration and title information can be notoriously inaccurate... some states used "year first sold" as the model year and/or someone could have re-titled the bike and in the process it was identified as the wrong year/model.)

Hey everyone,

Thanks for the responses, I think I'm starting to figure it out.

I also forgot to mention that I've been mainly using the Clymer M412 manual (DT & MX series...) , as well as the Dt400E supplementary manual.

I did some further investigation on bikes serial numbers, and it appears that the engine may actually be a DT400D. I've uploaded some images to google drive that I'll link below. I'm not sure that it would matter, but I think that the bike is probably Canadian as well.

Looking at the DT400c wiring diagram, it seems to match up with the bike for the most part, so it looks like I'll be going that route. I was convinced that I had a DT400e as I have a monoshock frame, but I guess its a bit of a frankenbike!

Here is a link to some of the pictures of the wiring, some of which I'll have to change, and serial numbers:
drive.google.com/drive/folders/1V-NAH_S5...jPCukle2FWp2rDfTK2z5

Thanks again, and if anyone has any other advice or comments, its always appreciated!

Poor old rectifier's looking sad.
Wondering where that black/white comes from so hope its not ignition kill wire fed into there.
Your green/red & straight green will be to do with charging.
Wiring give me a headache when its not straight forward.

By the VIN, it's a 1978.  The Tech Library here is a great resource for info like that and also manuals for many models.

CDI's die on the 360's and 400's fairly often.  Someone could have just swapped over an earlier ignition system. It bolts right up physically.  Or maybe Canada got the earlier ignition on their bikes...  I know on some of the RD's, Canada got different ignition/charging systems than we did in the US.