Issue with ignition switch

[last337]

1982 GS 1100 ES been sitting up a while. Go to start the other day and no reaction to start button. It had happened in the past that occasionally it wouldnt respond immediately to the start button. However, holding it for a moment it would eventually turn over and continue until I got it started. If I put a screwdriver across the poles on the solenoid I hear the starter engage just fine. I pulled the right hand assembly and checked and everything looks fine. Pulled clutch switch and nothing looks out of order there. I jumped the two pins on the clutch switch and grounded the button on the starter button and no reaction. I am not really sure where to look next. What is between those two that I could check next? I assume I should start at solenoid and go back but not really sure what to jump/check/etc.

Thanks!

 

[tom203]

"...grounded the button on the starter button and no reaction. "

Hopefully not. The starter button feeds positive 12 volt to the clutch safety switch (and maybe a sidestand safety switch,I don't know) and then this positive juice wanders down to trigger the starter solenoid. Here's a wiring diagram that should be sorta close, follow the paths

http://members.dslextreme.com/users/bikecliff/images/GS1100G_1982_wiring.jpg

 

[Steve]

"...grounded the button on the starter button and no reaction. "

Hopefully not. The starter button feeds positive 12 volt to the clutch safety switch (and maybe a sidestand safety switch,I don't know) and then this positive juice wanders down to trigger the starter solenoid.

Tom is mostly correct, except for the part about the sidestand switch. Sidestand switches did not appear until the '82 model year, but were never connected to the ignition or starting circuits, they only turned on a light on the instrument panel to show the stand was down.

Clean the switch contacts in the housings. If you wish to bypass the clutch switch to eliminate that variable, it's easy to do.

.

 

[last337]

After cleaning everything up and reassembling I did what I should have done first and started with the volt meter. I know that the ignition button is working and the clutch switch are working by testing battery. At battery I have 12.15v at rest then down to 12.08 with clutch in and engaging ignition. At poles coming from ignition on solenoid I get approx 8.4v with ignition engaged. If I jump the poles going to starter it does engage for a second until it arcs out. Is it my solenoid? Seem to remember just changing that thing last summer. Or is 8.4 not enough at solenoid to engage?

 

[Steve]

At 8.4 volts, you should be looking at changing your battery.

Voltage while trying to start the engine should be over 10 volts, preferrably closer to 11.

.

 

[last337]

Does it require 12 volts at the smaller posts on the starter relay that go to the coil to make the relay click? I am getting 8.4 volts between those posts when ignition is engaged but dont hear it click so I am thinking it may be bad. I do have 12.15 at the battery and if I jump the larger posts on the relay it does engage the starter so I am thinking it either starter relay or maybe something causing voltage drop between ignition and relay.

 

[Gorminrider]

if you disconnect the starter motor from the solenoid, you might hear it click. .... If your starting motor is not spinning, it draws more current and that might explain the 8 volts you see. Also, Your battery seems to be more than half-baked...12.15 volts at rest (with NO load) is a battery on it's way out. so it might be just your battery -it takes a lot of power to spin that big motor!

You can use a car battery in place of your little MC battery....try that. I always do, if there's trouble to shoot in starting orelectrics...saves straining the little mc battery. They are only meant to start a bike where everything works properly. If starter doesn't spin properly,then your starting motor might need cleaning up,

 

[JTGS850GL]

After cleaning everything up and reassembling I did what I should have done first and started with the volt meter. I know that the ignition button is working and the clutch switch are working by testing battery. At battery I have 12.15v at rest then down to 12.08 with clutch in and engaging ignition. At poles coming from ignition on solenoid I get approx 8.4v with ignition engaged. If I jump the poles going to starter it does engage for a second until it arcs out. Is it my solenoid? Seem to remember just changing that thing last summer. Or is 8.4 not enough at solenoid to engage?

If you have 12.08 at the battery but only 8.4 volts at the solenoid, then you have a some switch contact or wiring/connector issues. That's way too much loss along the way.

You need to systematically trace down your voltage levels starting at the main fuse and progressing along the way toward the starter solenoid. Pop out the first two fuses from the top in order keep the battery from getting drained by the headlight and instrument lights. Keep one lead of your volt meter on ground. You can use the -batter terminal if you like. Turn the ignition on and press the starter switch. Measure the voltage at the + battery terminal, the main fuse output (left side of second from the bottom fuse), ignition switched fuse (third from bottom) and then measure the voltage at the starter solenoid. Not the big wires but the small yellow/green wire going to the solenoid. You can first bypass the clutch safety switch to eliminate that as a possible cause. Compare the readings and see where the biggest drop in voltage is. Report back.

 

[SailEXIT]

Back in the day I had a similar problem.

It turned out the starter motor was bad.
When I pulled it out the resistance on the motor windings was quite high, 500 OHMS.
The new one was a lot less resistance.
I cannot recall exact readings but it was less than 50 OHMS.

If yours has a big resistance it would account for the large voltage drop.

Shaun