I looked up a 91', I'm not sure what year your machine is. Your start button should send ground when you press it. You should have a ground signal on the Red/white wire from your start button to the soleniod. The blue/white at the soleniod is power that comes from the inhibit relay. The inhibit relay needs a signal from the CDI to let the machine start. this is a ground signal on the yellow/black wire. My guess is you're not getting a signal from the CDI because of a safety switch. Just jump the Brown and Blue/white wires at the inhibit relay and as long as you're getting ground from the start button it should start. Using a test light for this kind of troubleshooting can be tricky because your light may light up from the voltage passing through the soleniod and not because there's power there. In other words, you may not have power at the button, you may be seeing the power coming into the soleniod on the blue/white, traveling through the soleniod coil and then up the red/white to the button. It's not as complicated as it may sound, start at the button, look for a ground. If you're not getting a ground signal out that's your problem. If you are getting ground out of the button, it's your starter inhibit relay. hope this helps you.