I'm having trouble figuring this out. 1985 FJ1100. Bike starts and runs fine in neutral with the kickstand up. When I lower the kickstand (with bike still in neutral), the starter cranks over but the bike won't start. When running in neutral, if I lower the kickstand, the bike dies. If I pull the clutch in, bike will run in neutral or in gear with the kickstand down (or up). And when the bike is in neutral, the neutral light on the dash always lights up.
so far I tested the kickstand safety switch and I get no continuity when it is down and low resistance (about 40 ohms) when it is up. It's supposed to have full continuity (0 ohms) when up, so I don't know if 40 ohms is close enough to full continuity, or not.
I also tested the side stand relay and the results don't make any sense to me. The resistance across the powered leads reads 75 ohms which is within spec. When I apply power to these leads, I can hear the relay clicking. With power applied, I have no continuity (infinite resistance) across the other two leads, and without power, I have full continuity (no resistance). this is the opposite of what should happen, according to the service manual.
I haven't tested the neutral light switch yet. But the green neutral light is working. It is possible to have the neutral light working but the switch failed ??
I'm a little lost. Hopefully my description above isn't too confusing.
I thought that what you are describing is right. Is what you're doing all with the bike on the centre stand?
It's a safety switch to stop you riding off with the side stand down. Unless i'm reading it wrong.
Mine starts and runs in neutral with the side stand down (with and without the clutch pulled in).
If pull in the clutch and put the bike into gear with the engine running and the stand down, the bike cuts out, so I can't ride off with the side stand down. That's the way it's supposed to work :good2:
Quote from: Billy Bananahead on February 26, 2026, 06:50:34 AMI thought that what you are describing is right. Is what you're doing all with the bike on the centre stand?
It's a safety switch to stop you riding off with the side stand down. Unless i'm reading it wrong.
You're reading it wrong. The bike will not run (no ignition) in neutral with side stand down. That's my problem.
Quote from: Millietant on February 26, 2026, 07:43:46 AMMine starts and runs in neutral with the side stand down (with and without the clutch pulled in).
If pull in the clutch and put the bike into gear with the engine running and the stand down, the bike cuts out, so I can't ride off with the side stand down. That's the way it's supposed to work :good2:
Quote from: Millietant on February 26, 2026, 07:43:46 AMMine starts and runs in neutral with the side stand down (with and without the clutch pulled in).
If pull in the clutch and put the bike into gear with the engine running and the stand down, the bike cuts out, so I can't ride off with the side stand down. That's the way it's supposed to work :good2:
Yes, I'm aware of how it is supposed to work. Mine won't run in neutral with the side stand down. That's what I am trying to troubleshoot.
It could be a bad diode in the diode block #27 on the factory manual schematic.The kickstand relay contacts when closed ground out the ignition control and prevents the spark plugs from firing. When the kickstand is up it closes the switch and gives the kickstand relay coil a path to ground energizing the coil and causing the relay contacts to open up ungrounding the ignition module and allows spark. There is a second path to ground for the kickstand relay coil that goes through a diode to the nuetral switch to ground. If that diode goes out then the only way to ground for the kickstand relay is through the kickstand switch.
The schematic .
Do you have the standard clutch master cylinder fitted, I fitted an FJR1300 clutch master to mine that had three prongs on the clutch switch instead of the FJ's two and no matter which way the wires were fitted on the prongs everything seemed to work backwards to normal, like bike would start in gear with clutch out etc.
I had to pull the switch apart and delete one prong and bend and move another one around so the plug would fit on and now everything works like it should, had me stumped for a while though.
Quote from: Bones on February 26, 2026, 02:32:47 PMDo you have the standard clutch master cylinder fitted, I fitted an FJR1300 clutch master to mine that had three prongs on the clutch switch instead of the FJ's two and no matter which way the wires were fitted on the prongs everything seemed to work backwards to normal, like bike would start in gear with clutch out etc.
I had to pull the switch apart and delete one prong and bend and move another one around so the plug would fit on and now everything works like it should, had me stumped for a while though.
My clutch switch has only two prongs...
Quote from: T Legg on February 26, 2026, 01:45:37 PMIt could be a bad diode in the diode block #27 on the factory manual schematic.The kickstand relay contacts when closed ground out the ignition control and prevents the spark plugs from firing. When the kickstand is up it closes the switch and gives the kickstand relay coil a path to ground energizing the coil and causing the relay contacts to open up ungrounding the ignition module and allows spark. There is a second path to ground for the kickstand relay coil that goes through a diode to the nuetral switch to ground. If that diode goes out then the only way to ground for the kickstand relay is through the kickstand switch.
You may be onto something. I'm looking through the wiring diagram and circuit diagram and if one of 2 the diodes that supply current to the neutral switch failed open (no current flow), it might explain what I am seeing. I'll need to pull that diode block and test it with the wiring diagram. Good thought. I'm away from home at this time and returning in a week. I'll report back.
Quote from: Gearbox Paul on February 27, 2026, 09:49:52 AMQuote from: T Legg on February 26, 2026, 01:45:37 PMIt could be a bad diode in the diode block #27 on the factory manual schematic.The kickstand relay contacts when closed ground out the ignition control and prevents the spark plugs from firing. When the kickstand is up it closes the switch and gives the kickstand relay coil a path to ground energizing the coil and causing the relay contacts to open up ungrounding the ignition module and allows spark. There is a second path to ground for the kickstand relay coil that goes through a diode to the nuetral switch to ground. If that diode goes out then the only way to ground for the kickstand relay is through the kickstand switch.
You may be onto something. I'm looking through the wiring diagram and circuit diagram and if one of 2 the diodes that supply current to the neutral switch failed open (no current flow), it might explain what I am seeing. I'll need to pull that diode block and test it with the wiring diagram. Good thought. I'm away from home at this time and returning in a week. I'll report back.
Resolved. Got home last night and tore into that this morning. I pulled the diode block off the bike and tested both diodes that are connected to the neutral switch. Sure enough, the diode between the Blue/Yellow wire and the Sky Blue wire had failed and had no current flow in either direction. Other diode tested fine. I had some 1N4001 diodes at home from another project, so I bypassed the failded diode and spliced in a 1N4001 diode between the two wires. Works as it should now. Good call T Legg.
I'm glad to hear you have it fixed.
A good color coded complete wiring schematic really helps. I keep a copy of it in my tool pouch and a picture on my phone. The Yamaha owners manual that comes with the bike has a complete schematic but its point to point not set up like a ladder diaghram also very small and hard to see without a magnifying glass.
Quote from: T Legg on March 06, 2026, 05:26:22 PMI'm glad to hear you have it fixed.
A good color coded complete wiring schematic really helps. I keep a copy of it in my tool pouch and a picture on my phone. The Yamaha owners manual that comes with the bike has a complete schematic but its point to point not set up like a ladder diaghram also very small and hard to see without a magnifying glass.
Thanks again. I found the circuit diagram in the service manual unnecessarily confusing regarding the wiring around the diode and the clutch switch. I see that you've used white out and redrew some of the wiring lines on your marked diagram to clarify it. I found your version of the electricial circuit much more useful than what is in the service manual.
Also, the testing information for the side stand relay, on page 6-18 of the service manual, is incorrect. The manual says that the relay contacts should close when the coil is powered up, and open with no power to the coil. That's wrong, the relay contacts are closed (0 ohms) when the coil sees no power, and they open when the coil is powered up.
Quote from: Gearbox Paul on March 07, 2026, 09:43:33 AMQuote from: T Legg on March 06, 2026, 05:26:22 PMI'm glad to hear you have it fixed.
A good color coded complete wiring schematic really helps. I keep a copy of it in my tool pouch and a picture on my phone. The Yamaha owners manual that comes with the bike has a complete schematic but its point to point not set up like a ladder diaghram also very small and hard to see without a magnifying glass.
Thanks again. I found the circuit diagram in the service manual unnecessarily confusing regarding the wiring around the diode and the clutch switch. I see that you've used white out and redrew some of the wiring lines on your marked diagram to clarify it. I found your version of the electricial circuit much more useful than what is in the service manual.
Also, the testing information for the side stand relay, on page 6-18 of the service manual, is incorrect. The manual says that the relay contacts should close when the coil is powered up, and open with no power to the coil. That's wrong, the relay contacts are closed (0 ohms) when the coil sees no power, and they open when the coil is powered up.
When trying to figure out a problem on my bike I too found the diaghram in the factory manual didnt make sense and couldnt possibly work as drawn. I redrew the lines to make it work . Later I traced out the wiring diagram in the owners manual that comes with the bike and found that it matched my redrawn schematic and that the factory repair manual was incorrect.
I am having the same issue (not running with side stand down while in neutral) on a 1990 FJ1200 that I am fixing up. I don't see a diode block like on the FJ11, does any one know where diodes might be physically located in the wiring harness? If I am reading the wiring diagram correctly they do seem to exist but not in a big block like the older bikes.
Open to other ideas of solutions. My clutch and side stand switches are all working as expected when tested with a multi-meter and the neutral light comes on when in neutral and turns of when in gear.
Thanks!
From what i remember there is a diode in the wiring loom. It's hard to locate without actually cutting open the loom casing. It's somewhere between the headstock and fuses. Sorry i can't be more helpful. I'll see if i can find the one i replaced and post a picture.
I'm sorry but i've lost the diode that i took out of the FJ loom but here's some info and the diode universal symbol > https://www.pcbasic.com/blog/diode_symbol.html
If you look in the Haynes Book of Lies at the wiring diagram then the symbol is there in the loom, just look for the symbol, but that is only on 1986 and 87 models. That's why i call it the Haynes Book of Lies as it could have been omitted regarding later models.
But looking at the wiring diagram could you bike have a problem with the side stand relay or is that earlier models only?
The most common issue with the side stand switch is the switch itself....a simple continuity test on the switch leg will identify any side stand switch problem.
Thanks for the responses guys. I did test the side stand switch with a multi-meter and it appears to be functioning correctly. I currently have the switch bypassed but would prefer if everything was fully functional.
Quote from: JTNWEvo on March 24, 2026, 12:34:35 PMThanks for the responses guys. I did test the side stand switch with a multi-meter and it appears to be functioning correctly. I currently have the switch bypassed but would prefer if everything was fully functional.
If the side stand switch is functioning correctly how are bypassing it ?
If you are just "shorting" it out, then the problem could lie between the "bypass"(shorting) and the switch.
The switch goes to earth , have you checked that to be ok.
I test the side stand switch with a multi-meter on the plug. When the stand is up the circuit is complete and when it is down the circuit is open. I have a jumper wire on the harness side of the bike completing the circuit now to bypass the switch. The problem is the bike wont run with the side stand down when in neutral unless I am holding in the clutch. The neutral light is on.
Is there some other test I should do?
Thanks!