99% of the time the computer will not be the problem.

1. The big thing people run into is usually bad connectors (the female connectors will swell up and not make good contact all the time) where they plug into the ecm or sensors.

2. First you need to get a wireing diagram. They are free on the internet but you got to look. Make sure the diagram is for a US bike, they change from country to country and they note it in the diagram.

3. When cutting down a harness people sometime cut out a needed wire or connect an un needed wire. They do use the same color combinations in several places, so you have to watch out.

4. You need a connector view of the computer and each sensor.

5. The pins in the computer can be broken down into several classes.

a. computer power circuits (12 volts)
b. computer anti-theft circuits (usa uses 8 volts to turn on)
c. computer ground circuits
d. sensor power circuits (5 volts constant)
e. sensor ground circuits (different from computer grounds)
f. sensor returns (the variable voltage returned to the computer from the sensors to tell the computer what is going on.)
g. Power for the injectors
h. Power for the coils
I. Injector return to injector drivers (different color combination for each injector)
g. ignition return to coil drivers (different color combination for each coil.)

Computers usually complete a circuit by opening and closing the path to ground with a device called a "driver" or really a big name for an electronic switch or relay. The power or 12 volts should always be at the injectors or coil whenever the switch is on.

h. circuits for the cam sensor
i. circuits for the crank sensor
j. circuits for kick stand, starter over ride (usually need to be grounded)
k. drivers for fuel pump and fan control (for some reason left out by most harness cutters)

Once you realize that is all there is. Get a buddy a diagram and connector view and chase each circuit from the computer to the device. Most all sensors share the same ground, and 5 volt power supply this is a pretty quick check. Before removing the computer and harness check each sensor connector for 5 volts with a volt meter and a good ground with an ohm meter. If the volts and grounds all check out. Your next step is to remove the wiring harness and check from each pin on the computer to the coresponding pin on the sensor connector. If you find one that does not complete the circuit you found your problem. If they are all good try a different computer.

That old tip over switch works just like the anti theft wire but different. It sends a voltage back to the computer*** too high or too low a voltage and it turns the power to the coils, injectors and fuel pump off until it is again set upright and the key is turned off and on again..

Working on computers is **** "A PIECE OF CAKE" "DEVILS FOOD"


Hones Dad himself

Still no luck. Even bought another tip over switch and no change. At wicks end. Can't figure this thing out. HELP

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Call me 1-502-778-MUFF (6833) "NO MUFF TO TUFF"


Pull the connectors off of the--------- cam sensor, water temp sensor, Throttle position sensors both primary and secondary, air temp sensor, atmospheric pres sensor, vac sensor and the tip-over sensor.

Make sure you have a digital volt ohm meter and not an old needle analog type.

Go find a sewing needle, a pretty big one. devise a way to attach it to your pos lead on your meter.

With the key on check for 12 volts at each of the sensor connectors>>> Put uour meter on dc volts. Put the neg lead on a good motor ground.>>>>> Don't stick the needle in the hole,>>>>> this is how the connectors get swelled up and makes for more problems. DO YOU HAVE 12 VOLTS ??? I think the wire on the other end of the plug is red or might be green but each sensor shares this wire so they all should show 12 volts.

Put your meter on ohms leave the ground connected to the motor ground. take your needle and find the ground connector for each sensor, it should be attached to a brown wire with black tracer. Touch the needle to the connector do you have somewhere between 0 to 5 ohms resistance?

This usually finds your problem, almost bet it will be the cam sensor without power or ground.

If everything checks out ok as far as grounds and power, it's time to check your return wire from the sensor. This voltage changes so all we can look for is continuity from the sensor to the computer terminal.

Ever so often these return wires will ground out to the frame, or (+) power or to one another. This is very seldom.

If you have power to each of these sensors and a good ground and the return wires from each sensor to the computer.

It is time to check the 2 wires from the crank sensor to the computer, for continuity, shorts to ground and or power.

If they are ok you probably need to switch out with a known good... crank sensor, cam sensor, or computer.

They changed tip over sensors between 01 and 08 make sure you have the right year. I don't know if the plug is the same or different but they won't interchange. And they will not run if that tip over is anything but facing "UP" until you fix it.

Honest Dad himself