This thread is a little old and I have done a lot of fixes since I originally posted - I thought everything was fixed and it seemed to be for a little while but then the same old thing came back. Bike stalls after starting up and a flat spot after idle.
What changed this time around is things got worse (easier to find the root cause :-)) The bike would stall after starting as usual but it was really hard or impossible to keep it running - the front cylinder wasn't firing.
Its fuel related because with starting fluid it will start and stay running like it should. I took the injector off and it seems to be operating normally.
I should point out that during all this troubleshooting I developed a problem blowing the ignition fuse. It took about 20 fuses but I finally located a wire that passes through the frame near the back of the tank that had a nick in the insulation. If I hadn't seen the spark I probably never would have found it.
Anyway back to the injector. There are two wires to each injector, power (12V) and a signal wire. So I checked both injectors, each power wire had ~12v. I checked the signal wire while cranking the engine over. The rear cylinder was giving readings between 10 to 12 volts. The front cylinder was giving reading around 4.5 to 5.5 volts. I did not make note of the polarity.
So, I'm thinking the problem with the front cylinder is the signal from the ECM. So here is the question, does the ECM sound plausible or is there something else I'm not considering?
Thank you,
Joe
