Making a KTM 450 SMR Street Legal - Electrical

Discussion in 'Thumpers' started by duck, May 3, 2009.

  1. duck

    duck Banned

    Mar 19, 2004
    Seattle (Berkeley with rain)
    So, I just bought this thing and am new to KTMs. It was advertised as "I've got everything to make it street legal." Well, yeah, sort of. I don't think it's ever been street legal but at least I have a plate for it and the plate number is already on the title so registering it shouldn't be a big deal. I was told that it's been upgraded to a Trailtech stator and stuff.

    So here's what I got in my box of parts that came with the bike:

    1 - Four little Lockhart Phillips turn signals. I've already figured out how and where to mount these.

    2 - A nifty little aftermarket LED running/brake/license light that will fit nicely under the rear fender. I'll need to fabricate some mounting hardware to get that and the plate on the bike but I've got that figured out.

    3 - The rear brake switch is already installed. No connector on the end, just bare wires. I tested it and it works.

    4 - No front brake switch. But I've got a switch from a BMW in my basement and I've figured out a way to install that to work with the KTM brake lever.

    5 - A KTM headlight. I installed that today. The front brake line is a little short to make it over the front of the new headlight panel so I had to run it behind the panel. No biggie.

    6 - What I'm pretty sure is a non-KTM headlight/turn signal/horn combination switch. I used a continuity tester and have figured out the wiring on that.

    7 - No horn. I've got some spare horns in the basement so that's not a big issue.

    8 - No mirrors. At least for now I'll get some bar end mirrors on Fleabay so it's at least legal.

    9 - A KTM mystery wiring harness. I can read the KTM on the tag but no part number. From looking at the wire colors and some KTM wiring diagrams I've deduced that the little black box I've got attached to the harness is the voltage regulator/rectifier.

    Since the lights and switches are non-KTM they have different connectors and won't "plug-n-play" with the KTM harness I have. So I'm thinking that my best bet is to use the regulator/rectifier and some turn signal relays and just build my own wiring harness. I've done lots of electrical mods to my other bikes so I'm not a nOOb at wiring and I think it should all be pretty straightforward.

    So my plan would be to take what shows on the wiring diagrams as yellow and white wires from the generator, run those to the regulator/rectifier and then power my lights and horn from the yellow-red coming out of the regulator/rectifier.

    Does this seem right to those how know KTMs?
  2. plugeye

    plugeye MC rescue

    May 11, 2007
    Garland, Texas USA
    titled & plated, your better than 90% there.
    here you can use a squeeze-bulb bicycle horn
    we dont need turn signals or a front brake switch
    and one mirror is enough, dont know about washington though
  3. coffeestained

    coffeestained post nihilist

    Apr 19, 2009
    asheville, nc
    I bought the exact same bike with the exact same issue! I couldn't figure out the ktm mystery wiring and baja designs refuses to give you any clues if you try to buy any of their conversion pieces individually like they will if you buy the $500 kit. I got the horn, headlight and brake light working and called it good (hand signals legal here). I made a point to avoid riding that bike in traffic anyway so it didn't matter. Sorry no real help from me...just found the similarity ironic. That bike is a blast!
  4. duck

    duck Banned

    Mar 19, 2004
    Seattle (Berkeley with rain)
    The plot thickens.

    I emailed the following picture to Trailtech tech support guys to see if they could be of help in determining what I've got.


    Their reply was that it didn't look like theirs but was probably stock EXC Parts. From looking at a few EXC wiring diagrams and the wiring colors I think they may be right.

    Here's the wiring harness that came in the box of parts with the bike. The guy told me at was a Euro EXC harness but given other misinfo from him who knows? (He bought the bike a couple of years ago and didn't do much with it.)


    The part number on the tag is worn and hard to read but I THINK it is 594.11.07?.000

    Here's the voltage regulator on the wiring harness:


    From the KTM wiring diagrams I've looked at the colors to it's connector seem to agree: Brown, Yellow, White, Yellow-Red:


    Here's a sample from a KTM EXC wiring diagram which leads me to beleive that I mihgt be able to just connect the voltage regulator to the yellow and white wires and get 12V DC out of the Yellow-Red wire: (with the brown wire grounded of course)


    So the question becomes how many watts can I get from the stator?

    I pulled the bulb from the EXC headlight I've installed and it says it's 35/35W.

    In addition to that I need to run an LED tail light setup (as LEDs that can't draw very much current) and four little Lockhart Phillips 122-0031 turn signals.

    In the meantime I fabricted some stuff and got the LED tail light and plate mounted under the rear fender. (I put the turn signals up at a 45 degree angle because it looked like the right one might get melted by the exhaust if pointed straight to the side.)

  5. mattis

    mattis n00b

    Apr 21, 2009
    Stockholm, Sweden
    Very interesting. Keep it up!
  6. duck

    duck Banned

    Mar 19, 2004
    Seattle (Berkeley with rain)
    OK, so I gave up on the KTM wiring harness. Time to get down and dirty and just build my own.

    Here's what came with the bike that I'll use:

    KTM 35W headlight
    KTM voltage regulator/rectifier
    4 Lockhart Phillips 122-0031 turn signals
    Rear brake switch (the only part the PO actually installed)
    Aftermarket LED brake/tail/ license light
    Aftermarket headlight/turn signal/horn combo switch

    Here's what I've bought:

    Turn signal relay ($9)
    5 Ah 12V sealed lead acid battery ($15 shipped)
    Four slot aux fuse block ($9 shipped)
    Bar end mirrors ($25)
    (I'll probably need to spend another $10 on open-ended grips for use with the bar end mirrors)

    Stuff I've got laying around:

    TomTom Rider GPS (running some 3rd party software
    to serve as a large digital speedometer)
    BMW K75S dash pad with igntion switch/key - that looks like it will work OK on the KTM bars. It has a three position switch which I'll wire up so it's:

    1) Off and bike won't run
    2) On with no lights except the headlight will work if turned on at the headlight switch
    3) On with power to everything and street legal

    If it looks like I've got enough spare power once I've got things going then I'll probably wire up some Symtec heated grips($40) to AC in the fall.

    I have some spare sheet aluminum in the basement so I plan to make my own mounting plate for under the seat and mount the following components to it to keep things organized:

    Voltage regulator
    Power relay
    Turn signal relay
    Fuse block

    For grouping/protecting the wires I have a cheap local source for various sizes of heat shrink tubing in four foot lengths.

    Here's a schematic for the wiring that I drafted yesterday. I plan ro run the headlight on AC and everything else on DC.


    Everything should be here by next week and I'll dig in.

    Pictures and results to follow sometime in the near future.