02-08-19, 06:01 AM
Does the bike have an alarm fitted? After it cut out did the starter motor turn the engine over? If it did that rules out quite a lot. For the starter to turn over 12V has to get to the cut-off relay. For 12V to get to the cut-off relay it has to go through the 12V circuit in the ignition switch, the ignition fuse and the kill switch so if the starter turned over you could assume all those components must be good.
If the starter turned over the ground to the cut-off relay must have been good too. Were you in neutral when you were cranking the engine? If so the ground from the neutral switch must have been good and it must have got as far as the cut-off relay. The ground from the neutral switch also should have gone to the ignitor and that should have been enough to start the engine but it didn't start so the ground from the neutral switch was good but it didn't make it back to the ignitor. Also when the bike cut out it was in gear so that means it cut out when the ground going back to the ignitor was coming from the side stand. So that means ground couldn't get back to the ignitor from either neutral or the side stand so that would suggest the open must have been at a point that is common to both of them. The most likely common point is the ignition switch or the connectors to the alarm. Or it could be right at the connector to the ignitor.
If the bike cuts out again you can test the theory by checking for ground at the ignitor when the bike is in neutral and the key is on. There are two ground wires at the ignitor, both are black. One is a permanent ground, the other one is the switched ground from the neutral and side stand. You're interested in the switched ground. If you turn the ignition switch on and put the bike in neutral, set your multimeter to DC Volts and put the red lead on the battery positive and the black lead on the black wires in the ignitor connector you should see 12V on the meter. With the leads still attached turn the ignition off. If you're on the permanent ground the meter will stay at 12V. If you're on the switched ground the meter will go to OL or if the switched ground is open all the time because of a fault the meter will read OL all the time and that would prove the fault.
All that is guess work though because we still don't know if it's actually losing spark or not. If it's running now you won't be able to test the ignitor for the switched ground but you can still visually check the wiring and connectors around the ignition, alarm connectors and ignitor and hopefully you'll see something obvious like a frayed wire or a corroded connector. If you can't see anything obvious you'll have to wait until the bike cuts out again and then check for spark. If there's no spark check for the switched ground at the ignitor.
If the starter turned over the ground to the cut-off relay must have been good too. Were you in neutral when you were cranking the engine? If so the ground from the neutral switch must have been good and it must have got as far as the cut-off relay. The ground from the neutral switch also should have gone to the ignitor and that should have been enough to start the engine but it didn't start so the ground from the neutral switch was good but it didn't make it back to the ignitor. Also when the bike cut out it was in gear so that means it cut out when the ground going back to the ignitor was coming from the side stand. So that means ground couldn't get back to the ignitor from either neutral or the side stand so that would suggest the open must have been at a point that is common to both of them. The most likely common point is the ignition switch or the connectors to the alarm. Or it could be right at the connector to the ignitor.
If the bike cuts out again you can test the theory by checking for ground at the ignitor when the bike is in neutral and the key is on. There are two ground wires at the ignitor, both are black. One is a permanent ground, the other one is the switched ground from the neutral and side stand. You're interested in the switched ground. If you turn the ignition switch on and put the bike in neutral, set your multimeter to DC Volts and put the red lead on the battery positive and the black lead on the black wires in the ignitor connector you should see 12V on the meter. With the leads still attached turn the ignition off. If you're on the permanent ground the meter will stay at 12V. If you're on the switched ground the meter will go to OL or if the switched ground is open all the time because of a fault the meter will read OL all the time and that would prove the fault.
All that is guess work though because we still don't know if it's actually losing spark or not. If it's running now you won't be able to test the ignitor for the switched ground but you can still visually check the wiring and connectors around the ignition, alarm connectors and ignitor and hopefully you'll see something obvious like a frayed wire or a corroded connector. If you can't see anything obvious you'll have to wait until the bike cuts out again and then check for spark. If there's no spark check for the switched ground at the ignitor.