KDXRIDER.NET

Here's a pic of my 1981 KDX250 that was given to me.
I washed her a little bit rebuilt and cleaned carb. Cleaned reeds intake. She fired up second kick ran smooth sounded strong! But she died 10-15 seconds later.
Now I have no spark, I pulled flywheel it checks out. Removed charging coil sanded contacts made them nice again. Put timing back to my marks. Bike ran fine where it was set. I have volatage from stator to yellow wire 10v-20v power to green white wire 16-20v and power to coil ground wire and green white wire before coil. I tested from ground to plug end cap and it bangs multimeter out to MAX... but no spark or very weak spark out of plug. It ran just fine then no more..?

I work on bikes and engines etc for a living. But not much Two stroke.
Whats going on?

This may sound obvious, but try a new spark plug.

Check continuity of the spark plug wire.

Be sure there's good metal-to-metal contact where the coil bolts to the frame.

Look up multimeter test values for all the electrical components. This will probably require purchasing a manual. They're cheap on eBay.

This bike has an electronic ignition, right? i.e., no mechanical breaker points?

Once you get a manual, you'll be able to troubleshoot the electrics much easier than by following the "guidance" of interweb yahoos such as myself.

sometimes the spark plug boot literally screws onto the wire. in this case, you could cut the wire about a half inch or so to expose fresh wires inside and screw the boot back on

Ill check and cut the plug wire today and try that..
I got some more useful information on here in regaurds to testing my electrical system.