Ladies and Gentlemen my latest nightmare. I got this bike around a month ago, it was gifted to me. So far it's been a headache as I move forward with one repair it takes 2 steps back. I have currently a no spark condition so I focused on that, reading on some threads (especially TwoWheelNation's) I found that the bike had a rat nest near the oil sensor and the wiring to the pickup coil which was chewed after i traced it from the ICM. after replacing that wiring with a used wiring harness that was intact. I crank the bike with the spark plug connected to the coil and it shoots one spark and has refused to do so after. now I know about the zener diode issue before all of this and decided to cut that off (had to replace ignition) and replace it with a DC/DC converted which is forcing 8.9 V into the pink wire which reaches the ICM. Gentlemen I am lost and heavily frustrated with this motorcycle and have come to a crossroads. Any advice on why the coils, which had 12V before have now decided to have no voltage?

 

Easiest way to find what’s wrong is tracing flow of electricity from source to destination measuring at each junction. You’ll get series of measurements like this:

battery 13v -> 13v -> 13v -> 13v -> 13v -> 0v <- ahAH!! -> 0v -> 0v -> coils

Problem is obviously between that point where you measured 0v and previous one that
did have power. So measure in sequence and post your measurements:

1. battery, volts = ??
2. red wire leaving starter-solenoid, volts = ??
3. red wire going into ign-switch, volts = ??
4. key ON, red/blk wire leaving ign-switch, volts = ??
5. red/blk wire going into fusebox, volts = ??
6. blk wire leaving fusebox, volts = ??
7. blk wire going into start/stop switch connector, volts = ??
8. start/stop=RUN
9. blk/wht wire leaving start/stop switch connector, volts = ??
10. blk/wht wire at coils subharness connector, volts = ??
11. blk/wht wire at each coil’s connector, volts 1-4 = ??


Once we have all the numbers, we can home in on where power stops. Lots of times it’s corroded or broken terminals inside connector or broken wires themselves.

 

you aren't checking spark by using the bell of the carburetor as a ground, are you? the carburetors are isolated.

 

First of all, thank you for giving me a hand with this.
1. 13.3V
2. 13.3V
3.13.3V
4. 13.1V (Battery is draining a bit just came off maintainer)
5. 3 of the Red/Blk wires in the fuse box V for all of them (12.9V)
6. 12.9V
7. 12.9V
9. 12.6V (battery is still at 12.9)
10. 12.5V
11. all coil connections show 12.5V across the board for the blk/wht wire, previously I had no power coming through here.

 

Not at all will give this a shot when I test for spark again.

 

Wasn't recommending that you check it that way, it just looked like in the photo that that's what you were doing. you wont get spark that way because the carburetors are isolated from ground. plus its probably not a good idea to check for spark right next to raw fuel delivery.

 

Ah sorry, my first time working on a motorcycle.

 

no worries. I have a '99 also and love it. on the clutch cover, there will be a connector coming out of the top of it with a yellow and white wire. unplug that and take an ohm reading of the 2 wires going into the engine. what is that resistance measurement? this is where I lost spark when I first got my bike.

 

The resistance to the pickup coil yelllow wire and yellow/white wire?

 

Yes.