XR500R wiring help

[Cory1]

hi there, I`m having some issues trying to wire up a 1981 Honda XR500R I bought from a friends Dad. The story goes they bought this bike used and he rode it for a couple years. Then the CDI box crapped out and they took the box off to find a replacement. Fast forward 3 years and its still sitting there not running, with the wiring hanging all over. So I check the bike over and it`s got compression and seems pretty solid. I buy a new replacement CDI box and get to wiring it up. Well this is where the problem starts. The wiring has been mostly stripped out of this bike. No lights at all, just the basics. So the manual shows the alternator has two wires coming off it, but this motor has 5 wires. I googled the motor number and find out its an 1982 that someone put in the 1981 frame. So now I`m totally confused as to what I need to do. My friend and his Dad both said the bike ran with the exact CDI box I bought, so the previous owner had it figured out at some point. 

I've added a few pics. The first is the wires coming off the Alt. the 2nd is the wiring for a 1981 and the 3rd is a pic of the motor # showing its an 82. Does anyone know what I need to do to get this running?

[S.O.A.N.Z]

PD02E is XL500 - 82

[S.O.A.N.Z]

correct diagram here for xl500 82

Edited October 27, 2017 by S.O.A.N.Z

[ThumperCurtis]

@Cory1 First we need to get the proper wiring diagram. That diagram is completely wrong for the engine. I've re-wired 4 different bikes and Honda keeps a similar theme on its wiring. From the wires you have this is my best guess until we see a diagram or you trace the wires into the stator cover and show me that:

Black/Red - most likely the pulse from the stator to CDI to the ignition coil

Pink - Positive Voltage signal that goes to Regulator/rectifier; this is for 12V accessories past the battery

Yellow - negative voltage signal that goes to Reg/Rec; this is for 12V accessories past the battery

Green/Red - typically this is for a neutral indicator light to the dash cluster

White/Yellow - return feedback loop from run/stop switch?!? 

Green - GROUND (always)

Black - power typically past the CDI or key switch

 

[S.O.A.N.Z]

yellow & yellow & white + pink run to reg. rec. for lights

green & red - neutral light

only ones you need to worry about are black & red - to cdi

+ pick-up coil wires to cdi - coming out of clutch cover

 

Edited October 27, 2017 by S.O.A.N.Z

[S.O.A.N.Z]

the diagram cory1 has is the xr diagram

[ThumperCurtis]

Updated:

 

3 minutes ago, ThumperCurtis said:

Black/Red - the pulse from the stator to CDI to the ignition coil

Pink (NOT USED for RUNNING ENGINE) - Positive Voltage signal that goes to Regulator/rectifier; this is for 12V accessories past the battery

Yellow (NOT USED for RUNNING ENGINE) - negative voltage signal that goes to Reg/Rec; this is for 12V accessories past the battery

Green/Red - neutral indicator light to the dash cluster

White/Yellow - Ignition power going through a regulator to the Black side of the Ignition Coil (this is your spark power) 

Green - GROUND (always)

Black - power typically past the CDI or key switch

 

[Cory1]

Wow! Thanks guys for the info, that's awesome! I'm going to try and get this running this weekend. I'll let you know how it goes.

[David Hotelling]

Hi I got a 1981 xr 500 what wires Co into the cdi I got a white with a black wire comeing from the mag and got a blue with a green  I think this is the kill switch but I got a blue and yellow and a black and red with a black and white with two greens the are the cdi wirers what ones go where

 

[Chuck.]

Honda wire color codes, this chart is for street bikes but the same colors apply to offroad:

Edited February 16, 2020 by Chuck.

[David Hotelling]

Thank you for the info,but need to know where the cdi wires go to that are diffent colers then the one comeing g out of the bike

[Chuck.]

[David Hotelling]

On 2/18/2020 at 7:01 AM, Chuck. said:

You don't got info on the xr500r1981,or what the cdi wires do or r for thanks for the help

 

On 2/18/2020 at 7:01 AM, Chuck. said:

 

[Chuck.]

Wire color vs function are the same, just most of the pre 84 used bullet connectors so it was match the wire colors for both sides of the bullet.

 

[Bebolly]

Hi, sorry for reviving a post from the depths of hell but hoping someone can help me. I have an 81 xr500 had it running, tried to install a xl harness into it for lights etc, had an absolute failure and have now removed it all. Problem is now I can't get spark. I was using a test light at the end of each component to determine if power was getting through etc. Got to the coil and installed the test light on the input of the coil pack (output of CDI) and the clip to the motor, kicked it over and it goes like a dream, take the test light off and it stalls. Not sure wtf is going on!

[Trailryder42]

20 hours ago, Bebolly said:

Hi, sorry for reviving a post from the depths of hell but hoping someone can help me. I have an 81 xr500 had it running, tried to install a xl harness into it for lights etc, had an absolute failure and have now removed it all. Problem is now I can't get spark. I was using a test light at the end of each component to determine if power was getting through etc. Got to the coil and installed the test light on the input of the coil pack (output of CDI) and the clip to the motor, kicked it over and it goes like a dream, take the test light off and it stalls. Not sure wtf is going on!

Pull the rubber back on the plug boot, check the connector/wire union for looseness/corrosion. There's also a screw up inside the boot/connector. Make sure it's present/tight and the resistor is there. If you want, you can replace the resistor with the piece of copper wire, same diameter and length. Can't remember if it's 8 or 10 gauge. A lot of folks just use a steel bolt or screw but copper has the least electrical resistance.

There should also be a separate smaller gauge wire connected to the coil. Green I think. Be sure it's there and connected properly. 

[Bebolly]

Cheers mate, the coil to plug lead is pretty ratty so have ordered another anyway, but I'll try that in the am when I can see

[everlastneverfast]

Sounds like you have missed a ground connection. Module and coil need to be grounded.