I have just edited a wiring diagram for the 1988+ Ninja EX250. I have made this diagram easier to follow and added some detail.

This is version: US 0.3 (my version of the diagram)
As you can tell it's still in its very early stages as cannot be compared to my newer diagram for the 2008+ 250r, in terms on quality, posted here.

http://www.ninjette.org/forums/showthread.php?t=35886

Eventually, I will update this diagram to make it as best I can for you folks who need to troubleshoot or mod your bikes.


If you have ANY requests or suggestions, please leave a comment here and I will look into them and possibly update the diagram.


Here is a link to the diagram.

http://www.mickeywebpages.com/users/jon/ninja/Ninja_EX250_Wire_Dia.gif

good work there jon!

WELL THANKS FOR POSTING THE WIRING DIA. REALLY HELPED ME OUT AS i WAS LOOKING AT THE REAR LIGHTS YESTERDAY AND NOTICED THAT THE REAR TAIL LIGHT ASSEM ALSO HAS A PLACE FOR TWO MORE LIGHTS ON EACH SIDE OF THE MAIN RUN /BRAKE LIGHT LENS. i AM ASSUMING THAT THIS IS FOR JAPNESE OR EOURPEAN MODELS.. AND THAT THE US VERISIONS HAVE THE LOWER FENDER MOUNTED AMBER LIGHTS??? NO MATTER AS I PLAN TO ADD TWO BRAKE LITES IN THE FIXTURES FOR MORE BRAKIN LITE
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Nice! I've been looking for one somewhere and didnt want to but a service manual for one (even though I probably should anyway) Turtle i always picture someone yelling when their caps lock is on.. Don't know why..

jonthechron - it looks like the pic link in the first post is no longer active. Do you have that IMG stored anywhere else by any chance? If you let me know, I can point the link to the right place.

In the meantime, here's a page (http://faq.ninja250.org/wiki/Wiring_schematics_%26_diagrams) that has some of these similar wiring diagrams.

Yeah I was also wondering if there happens to be a mirror for the file... =\

just posted that same page myself , found it a few months ago , very excellent NINJA250.ORG

Here's the PDF of the PreGen wiring diagram. I'm sure I got it from somewhere around here, but for some reason it wasn't in this thread.

(The thumbnail looks funny, but the file opens fine.)

Thanx will come in handy soon.

I'm not able to open up the diagrams. I have the Haynes manual diagrams (A-MUCKIN-FAZING museum, kinda sketchy manuals lol) and I have a wire set that isn't identified in the Haynes diagram.

On my 2005 Ninja 250r, there's a wire pair I can't identify. It's well integrated into the harness so I THINK it's stock but I can't find info on it. It's bigger gauge than the rest (10 or 12g) .. one is black with a yellow trace (that one should be ground?) but the other one is white with a black trace. THAT one is throwing me. The pair shows full hot at all times without regard to key position (or even presence) and it ends in female spade connnectors at both ends with no apparent male spade connectors to *ahem* couple with - one end near the battery/junction box area and one end near the headlight end of things.

Any idea what I might be looking at?

Those are auxilliary power connectors. I use them to power heated gloves, GPS and espresso warmer on my bike.

Those are auxilliary power connectors. I use them to power heated gloves, GPS and espresso warmer on my bike.

God bless everything about what you just said, especially the part where it answered my question.

im reinstalling my wiring harness and i have come across a connector that is also stock to the harness. It has two wires leading into a two prong connector, the wires are both red/blue I have been searching to see if i am missing a part but I cant seem to figure it out. I do believe they may be the auxiliary leads but im not too sure, my bike has been in pieces for a couple years now... I dont see a wire or connection for a rear brake switch

WELL THANKS FOR POSTING THE WIRING DIA. REALLY HELPED ME OUT AS i WAS LOOKING AT THE REAR LIGHTS YESTERDAY AND NOTICED THAT THE REAR TAIL LIGHT ASSEM ALSO HAS A PLACE FOR TWO MORE LIGHTS ON EACH SIDE OF THE MAIN RUN /BRAKE LIGHT LENS. i AM ASSUMING THAT THIS IS FOR JAPNESE OR EOURPEAN MODELS.. AND THAT THE US VERISIONS HAVE THE LOWER FENDER MOUNTED AMBER LIGHTS??? NO MATTER AS I PLAN TO ADD TWO BRAKE LITES IN THE FIXTURES FOR MORE BRAKIN LITE
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how did you install two more lights??? was it a simple splice and tie in?

check this out: https://www.ninjette.org/forums/showthread.php?t=317840

here's some connectors that fit into factory harness turn-signal connectors.

What wires can I use to bypass this so I can use a toggle to turn on the power?

Mahalo in advance.

Connect toggle-switch + 100-ohm resistor like this to ignition-switch connector:

https://drive.google.com/uc?export=download&id=1Td98HZf4lGV9G5OyCRq6fjGZ_7vSQKX5

Connect toggle-switch + 100K resistor like this to ignition-switch connector:

https://drive.google.com/uc?export=download&id=1Td98HZf4lGV9G5OyCRq6fjGZ_7vSQKX5

Mahalo Danno, appreciate the info.

You're welcome!
Be sure to disconnect battery before working on this.
That white wire comes directly from battery and is hot full-time. :wave:
BTW - also edited original post to say resistor = ~100-ohms.

Thanks for this, the auxiliary power connectors what's the limits on them?

Here's the PDF of the PreGen wiring diagram. I'm sure I got it from somewhere around here, but for some reason it wasn't in this thread.

Here's the same thing (basically just a screenshot of it) in PNG format, since that's sometimes easier to view than a PDF these days. It's an Archive.org copy of the file on my site, so it should outlive me.

https://web.archive.org/web/20230520144012if_/https://www.invisibill.net/ninja/250/EX250F_Wiring.png (https://web.archive.org/web/20230520144012if_/https://www.invisibill.net/ninja/250/EX250F_Wiring.png)