1987 kdx resto & charging circuit

[kdx87]

Hi guys ive finaly done up my kdx even though it is a little rough, i spent the last few days strapping up and getiing it ready for rego, only problem is i cant seem to get it to charge, i had two wires one yellow and the other green that went to a 3 prong regulator and as i went to touch the BATT circuit it sparked wicled and popped a fuse' so i stuck a diode on which stopped the problem but it not charging' can anyone help me go through and debug this. Ill post some photos of my resto later when i get home

[kdx87]

Well i sorted out the charging circuit seems i had it wired to the regulator back the front "IQ strong here", and i popped a bulb, few more things to address, but for now just need the foot brake switch and a speedo of some sort, then going for rego. Trying to find how to upload images

[KDXGarage]

Good luck on the rebuild. No KDX's in the USA came with a battery, so most of us have no KDX experience with that.

[kdx87]

The bikes complete now, headlights, indicators, tail lights, horn, battery, charging circuit. Ill draw up a wiring diagram and share it with everyone so if they need a wiring diagram for air cooled kdx's it will be here, also the system was converted to 12v

[KDXGarage]

That would be great. Post a picture of your bike, if possible.

[kdx87]

Hi Jason, a little lost on how to post images,

all i get is

[kdx87]

It was supposed to be just the /img /img but oh well

Also i need some help with the speedo, i need a speedo here in Australia for rego and from what i believe the 86-88s have a speedo drive on the front wheel?, i was thinking of just getting a cheep speedometer that uses cable drive and just buy a cable and hook it up, will this work?, its the last thing i need before getting it plated.

[KDXGarage]

Click on Img. Put the address between the two tags.

You have to have the picture hosted on another site.

I am not sure on the speedo. No speedo on the USA KDX's.

[kdx87]

Not a problem, ill do that when i get home

Ill also start a new thread, and it will be for people restoring 86-88 KDX's with lights and gear as such, and especially for getting them regoed

[kdx87]

[KDXGarage]

DAMN, SON!! You have put the shine to it!


Thanks for the pics. It is always weird to see the battery / shock reservoir placement. In the USA, the shock reservoir is where your battery is.

[kdx87]

Thanks Jason,

It seems perhaps the Euro models came out like this, thats the original battery harness too, however this battery a little to fat for it, only thing non original on this bike would probably be the handle bars and a Talon rear sproket, but ill change that.

[Dekon]

Wow! That is nice looking.

[hbgod]

Looks sweet. Any chance we can get that wiring diagram? I'm in the process of doing the same thing to my 86.

[kdx87]

Hi there, every bit of wiring i did myself, however it can be easily done to other kdx's. ill draw a quick sketch up this afternoon, as a final version done in cad would take a bit of time.

[hbgod]

cool thank you very much, i get the basic idea of it any input is extremely appreciated. my biggest fault seems to be converting the 6v source to 12v to either charge the battery or run all the blinkers, horn, and such.

[kdx87]

Sorry about the delay, i worked flat out yesterday finishing the rear brake switch and the speedo, and then i fixed an oil leak. and then today i got a blueslip which is a vehicle inspection and safety check and then i got it road registered. Im still waiting untill next week untill i get my license. but man am i eager, you wont see many of these KDX's on the road today especially in NSW. ill upload pictures soon.

Now as far as the wiring system goes, for now what you want to find is a little 3 pronged black device, thats your regulator. Make sure it says 12v somewhere on it and check with multimeters with is the correct in and out. on my KDX i have a yellow and green wire coming from the magneto. Im not sure what the green wire is but the yellow wire is your power cable, im sure its similar or the same on other KDX's. You want to hook that wire up to the regulator and then install a Diode which will make sure its DC. after the diode wire it up straight to the battery.

[hbgod]

The only wiring difference i can see between the 87 and 86 is that i have 4 wires coming from my magneto and you only have 3. my trip meter also has an added wire as well(im not using my trip meter though). Im not sure what the green wire from the magneto is. book says you should only have a yellow, red/white, and black(green wires are for your trip meter and a green and white for the coil from the cdi). unless you have an 86 in which case youd also have a blue. but the yellow wire is the power wire for the headlight(stock). I have a clymer manual which has the wiring diagrams for 83-88.

How does the 3 pronged regulator use a 6v input for a 12v output? is it also a voltage booster as well as a regulator? Does it keep the battery charged? or is the 87 not 6v?

[kdx87]

86-88 are the same and all 3 have 4 wires coming out of the magneto and they are all 6v, so fare the green wire is useless and the yellow wire is the key here, current straight from the magneto is AC and voltage ranges considerably, you want a 12v regulator that caps the voltage from going any higher than 13.8v and hook it up directly to the battery this will charge the battery. However because the generator coil is weak expect the battery to only charge once 3500-4000rpm is reached. i have a trail tech digital computer thing on mine and the 86-88's like to idle at around 1800, the powerband is at 6000 and the absolute most it will rev too is 11000.

The 3 pronged regulator says 12v on mine so it must have been off a 89 or newer KDX, its not very powerful at charging and id go with LED's if your dualsporting.

[hbgod]

Im just going by what the manual says considering my motor and wiring harness are at a dyno shop right now finishing up the machine work and tuning. when iget it back ill double check it all. So far just about everything will be LEDs other than the headlight. already have LED blinkers.