12 volts at coils

[Guest]

I did the coil relay mod. some time back on the 450 winter project. And today since I can't seem to get bike to run right I checked the volts to the coils. Well I wasn't getting but a couple of volts from one coil and about 11.8 from the other. Checked it on relay, and what was on coil side also, got the same readings no matter where I took the readings. So replaced relay with new one and changed all connectors on relay and changed ones on coils. Seemed to solve the low volt readings. But bike seemed to run no better, so checked volts at spark plug ends(with bike not running and key on) and getting 11.5 on cylinder two, but only about 1.8 volts on #1. So unplugged white wire from coil to ignitor and got 11.8 volts at end of plug wire while white wire is unplugged. Reconnect white wire and volts drop to 1.8 again. Does this mean I have a ignitor problem or just a wire problem some where? (I plan on taking harness apart and following white wire, as soon as I have time.) terrylee

[rustybronco]

I did the coil relay mod. some time back on the 450 winter project. And today since I can't seem to get bike to run right I checked the volts to the coils. Well I wasn't getting but a couple of volts from one coil and about 11.8 from the other. Checked it on relay, and what was on coil side also, got the same readings no matter where I took the readings. So replaced relay with new one and changed all connectors on relay and changed ones on coils. Seemed to solve the low volt readings. But bike seemed to run no better, so checked volts at spark plug ends(with bike not running and key on) and getting 11.5 on cylinder two, but only about 1.8 volts on #1. So unplugged white wire from coil to ignitor and got 11.8 volts at end of plug wire while white wire is unplugged. Reconnect white wire and volts drop to 1.8 again. Does this mean I have a ignitor problem or just a wire problem some where? (I plan on taking harness apart and following white wire, as soon as I have time.) terrylee

The voltage is measured at the coil(s) on the orange/white wire(s). your trying to measure the voltage on the igniter (ground) side of the coils . the 1.8 volts you measured is when the igniter has grounded the coil in preparation for the firing of the coil. when the igniter opens (disconnects) the ground circuit from the coil, is when the the magnetic field collapses and induces current into the secondary (high voltage) side of the coil and the plugs "spark".

the igniter alternates this process from one coil to the other coil. when one coil is grounded, the other is not. that is the reason you are measuring 11.8 volts on the ungrounded coil, while on the grounded coil you are measuring close to 0 volts (1.8).

there is a procedure for checking the ignition system in the shop manual and, IIRC it's also on basscliff's site.

[terrylee]

Thanks Rusty, I should have known that, I had read about it before, but sorted of freaked when I got those readings. I will do the test and see what I get. terrylee