The older they get, the more problems we hear about.
Fortunately, the KX500 is one of the easiest to trouble shoot.
What should you check first?
This question will get you a lot of answers.
I say, check the cheapest and simplest things first.
Do you have a shop manual for your dirt bike?
If not, get one.
A shop manual will not only have the specs for your electrical system, it will also take you step by step on simple repairs to complete rebuilds.
Working on your Electrical system can be dangerous if you don't take the proper precautions.
I caught a bike on fire once because the spark plug lit off some fuel that had spilled earlier in the day, so..... Be careful!!!
Drain the fuel if required, empty the carb, remove the tank, what ever it takes to make it safe.
First, here is a picture of the KX500 Electrical system:
![Image](http://i644.photobucket.com/albums/uu165/oemcycle/kx500%20electrical%20made%20easy/KX500ELECTRICALMADEEASY-3.jpg)
As you can see, I included the wiring codes.
This system came off a 1994 KX500 but this system was unchanged from 1990-2004 and some parts are used as far back as 1983
![Smile :-)](./images/smilies/icon_e_smile.gif)
When checking electrical systems I always start with the simplest and cheapest things first.
So, the first thing I always check is the Spark Plug
Spark plugs can be a hot topic
![Laughing :lol:](./images/smilies/icon_lol.gif)
I like to run NGK plugs.
The NGK manual has the following plugs for the following years:
1983-1984 KX500 REGULAR B9EG, V-TYPE (GOLD) B9EGV, IRIDIUM BR9EIX
1985-1997 KX500 REGULAR B8EG, V-TYPE (GOLD) B8EGV, IRIDIUM BR8EIX
1998-2004 KX500 REGULAR BR8EG, V-TYPE (GOLD) N/A, IRIDIUM BR8EIX WITH A SOLID TERMINAL NUT
The spark plug gap for the 1983-2004 KX500 is .024" and the retail price is about 6.50 USD as of 10-27-12.
![Image](http://i644.photobucket.com/albums/uu165/oemcycle/kx500%20electrical%20made%20easy/KX500SPARKPLUGGAPPIC1.jpg)
![Image](http://i644.photobucket.com/albums/uu165/oemcycle/kx500%20electrical%20made%20easy/KX500SPARKPLUGGAPPIC2.jpg)
When in doubt simply replace the plug.
Just be sure to properly set the gap.
No, it will not come out of the box ready to go and using your eye to measure the gap simply isn't good enough.
Get a feeler gauge and set it.
As shown above, when using the feeler gauge the gauge should slip in with some resistance.
It should not be loose and sloppy.
***Important Information******Important Information******Important Information***
Many guys like to test their spark by removing the spark plug and kicking the bike over and watching to see if the spark plug sparks or not.
This method is fine.
However..... You must keep the ground electrode of the spark plug in contact with the engine at all times otherwise you can destroy your CDI and now you may have two problems to sort out and not just one.
Here is a picture of the ground electrode:
![Image](http://i644.photobucket.com/albums/uu165/oemcycle/kx500%20electrical%20made%20easy/KX500SPARKPLUGPIC2.jpg)
The next thing I check is the Stop Switch sometimes called a Kill Switch.
Here is the book info:
Fits 83-95 KX500 P/N 27010-1161 approx. retail price 34.00 USD as of 10-27-12.
Fits 96-04 KX500 P/N 27010-1350 approx. retail price 34.00 USD as of 10-27-12.
However, the switches for both year ranges work exactly the same way so you can mix and match if you need to.
![Image](http://i644.photobucket.com/albums/uu165/oemcycle/kx500%20electrical%20made%20easy/KX500STOPSWITCHPIC1.jpg)
You would be shocked how many times a 35 dollar switch kept a bike worth a few thousand from running.
You can test the switch with your ohm meter.
If you don't have one you can pick up a ohm meter from Radio Shack starting at about 25 dollars.
NOTE: Not all OHM meters have the same internal impedance values.
Just a quick note on impedance, impedance measures how easily a circuit conducts current when a voltage runs through it.
You measure impedance in ohms.
What this measurement tells you is how much of the voltage put into one end will make it to the other end.
The higher the resistance value is, the less voltage is making it through the circuit and usually meaning that something is getting hot
![Geek :geek:](./images/smilies/icon_e_geek.gif)
Your manual may or may not have those values recorded.
If the manual does not say what the impedance value should be they typically tell you what the part number for the correct OHM meter is.
Keep in mind that the impedance values will not make any difference for checking continuity, however, it will make a difference for checking resistance values.
Confused? Yeah, me too
![Very Happy :D](./images/smilies/icon_e_biggrin.gif)
Continuity is simply checking for any breaks in the wires.
Most OHM meters provide a Continuity setting.
In this picture I have my OHM meter set to check continuity.
Like a lot of other OHM meters my meter actually beeps when it is set to check continuity.
Some meters will light up or give you some indication that you have a good wire.
If you are not sure on your meter, set it to check continuity and touch the black and red leads together.
If it beeps or light's up then your good to go.
If nothing happens, read the manual that came with your meter.
You may have it set incorrectly or your battery may be bad.
![Image](http://i644.photobucket.com/albums/uu165/oemcycle/kx500%20electrical%20made%20easy/OHMMETERPIC1.jpg)
To check continuity of the Engine Stop Switch, set the ohm meter to check continuity and hold one lead to one wire and one lead to the other wire.
Have a friend push the button or get creative
![Very Happy :D](./images/smilies/icon_e_biggrin.gif)
You can use some alligator clips to hold everything together for you.
![Image](http://i644.photobucket.com/albums/uu165/oemcycle/kx500%20electrical%20made%20easy/OHMMETERPIC2.jpg)
If your ohm meter beeps when you push the button down then the switch is good.
If nothing happens when you push the button down and you know that you meter is good, then it's time for a new switch or disassembly, cleaning and re-testing of the switch.
You do not want to ride any motorcycle without a good stop switch!
If you don't have a ohm meter you can disconnect the kill switch and kick the bike over.
Some caution is in order because with the the kill switch disconnected you will not be able to easily stop your engine if it starts and decides to rev up to 25,000 RPM
![Shocked :shock:](./images/smilies/icon_eek.gif)
If the bike suddenly starts you can either quickly reconnect the kill switch or pull the spark plug wire off.
Once the kill switch is disconnected, kick the bike over again.
Still no spark?