Welcome to Netrider ... Connecting Riders!

Interested in talking motorbikes with a terrific community of riders?
Signup (it's quick and free) to join the discussions and access the full suite of tools and information that Netrider has to offer.

Looking for Honda CB125e wiring diagram

Discussion in 'Modifications and Projects' started by bluebie, Mar 26, 2016.

  1. Recently switched from a postie to a CB125e, and I'm looking to start modding the electricals, starting with USB power to keep my phone alive when it's acting as GPS navigation. I'd like to hook up some other stuff later too, which could get more complicated than just sipping power.

    On the postie, it was easy as pie to find wiring diagrams online, but I've had no luck with the CB125e. Wondering if anyone has any ideas how I could get ahold of one, before I dive in with a multimeter and try and figure it out for myself?

  2. Think it's also known as a GLH125 SH (?) so you might find something under that.
  3. Tried GLH125 SH, also looked for the US e-storm bikes wiring as they're supposed to be very similar, but couldn't find those either. Turning out to be surprisingly difficult!
  4. Yeah it's funny it's not in the electronic service manual as well. Maybe email Honda Aus or your local dealer and ask them for one.
  5. Emailed Honda Motorcycles Australia and they eventually got back to me! They sent this barely legible scan.

    CB125 - Wiring Diagram.
    • Funny Funny x 1
  6. Personally I'd just multimeter it.
    Hook in a relay directly off the battery and find a source such as the rear tail light that cycles when the ignition is turned on....from the relay run it to the front of the bike under the tank in a plastic loom hose.

    Just be aware that their isn't a great deal of headroom on the electrical system, I'd suggest shedding a few watts such as replacing dash wedge globes with LED's or if your going more drastic (ie heated handle bars) start replacing major lights.
  7. hooked up a 5v buck regulator and the 12v 0.4amps my phone uses charging at its max rate doesn't seem to affect the bike's running at all. I did use a multimeter, but I'm drawing off the power on the lighting circuit directly. no relay. no problems so far everything seems to be keeping up fine. system voltage doesn't seem particularly affected by it.

    I'm a bit cautious about using LED lighting because I had an experience with the Postie (cb110) where lights would blow from running too hot because system voltage would raise too high if any bulbs failed and weren't draining the system. In that way I'm a bit more paranoid about not drawing enough power than taking too much. easy to rip out some extra accessories on the side of the road, not so easy to deal with indicators not drawing enough power
  8. Just brief note on most bike alternator/regulator systems. The regulator on bikes are Shunt regulators so the load on the alternator is fairly static, to maintain the voltage the regulator places a direct short across the alternator periodically. This short reduces the voltage, the regulator senses that and removes the short. This is different from a car charge system which regulates by changing the voltage on the spinning part of the alternator, the rotor which alters the output voltage from the stator. This means, in a bike, the more power you draw the less work the regulator has to do. Up to a point, once you exceed the rating of the alternator the regulator can no longer do anything and you may burn out windings on the alternator. This is the dreaded stator fault.

    In your case charging your phone should be no issue, the system will have enough headroom to cope with it, from the drawing above there only appears to be one fuse the main fuse of 15A so you should not have any issue with that blowing. For peace of mind it may be worth getting a replacement fuse and taping it under the seat, that way if you do get that fuse blow you wont be stuck by the side of the road. (y)