Author Topic: Need some help trying to start bike with suspected frigged kill switch (Read 20638 times)

calj737 · « **Reply #50 on:** July 04, 2016, 04:33:38 PM »

If you still have your harness unwrapped, then look for locations where BLK is touching the frame or motor. That will blow your MAIN fuse in an instant.

BTW, I never suggested "unwrapping" your harness, only chasing Black connections and voltages through it.

b1jackson · « **Reply #51 on:** July 04, 2016, 04:52:22 PM »

No issues with unwrapping. I'm a visual learner and it helps me understand where all the pieces go. Harness has now been unwrapped from the steering stem, around the coils and all the way under the fuel tank to the air box. No issues there. Re-wrapped with shiny new tape. Same with the 4 inches or so that easily reachable going out of the harness into the fuse block.

The only spots not yet checked are where it drops in between the air box and the battery and the connections going into the little plastic triangular box beside the horn.

scottly · « **Reply #52 on:** July 04, 2016, 04:59:41 PM »

The problem isn't inside the harness wrapping. If the fuse blows only when the key is turned on, it means the short is after the switch. The black wire(s) are somehow connected to ground or a very low resistance load, such as the starter motor. When you were messing with the solenoid, did you happen to connect a wire to the post on the starter side?

b1jackson · « **Reply #53 on:** July 04, 2016, 05:38:23 PM »

No I didn't but the starter will be worth a closer look. Recall the PO said that he tried to start it without a ground hooked up and he thought he toasted the solenoid? Maybe there is a starter connection that took a jolt of juice and shorted out.

b1jackson · « **Reply #54 on:** July 04, 2016, 06:28:52 PM »

Quote from: b1jackson on July 03, 2016, 05:06:00 PM

No fuse in holder, key in off position

0.12v on left side of main fuse terminal and 12.5v on the right side

No fuse in holder, key in on position

0.0v on the left side of the main fuse terminal and 12.5v on the right side

I wonder after my recent tests if this earlier test when I was thinking it was fuse block sheds any light or narrow it down? Since I've taken fuse block out now and tested with an inline and it popped, could this mean a feed of 0.12 v into the line somewhere?

scottly · « **Reply #55 on:** July 04, 2016, 06:56:27 PM »

Your symptoms have changed since you first started. You now have a short circuit to ground on the common harness black wire, fed from the key switch. To locate the short without spending a small fortune on fuses, wire a light, like a tail light, with spades and replace the inline fuse with it. It will limit the current to a safe level, and allow you to unplug loads and view the effect: with a dead short, the bulb will be as bright as when directly across the battery terminals. With a normal, non-fuse blowing load, it will be dimmer. You might want to start by disconnecting the black wire between the harness and the kill/start switch.

b1jackson · « **Reply #56 on:** July 05, 2016, 02:42:55 PM »

Well would you look at this!

Being the newbie that I am, I thought I was into all the connections when I was in the headlight bucket and I cleaned and snugged every connection. Not realizing the black power junction is right here!

Unplugged the black wire to kill and the horn and had dash lights, signals. Plugged the horn back in and had beep beep.

Then plugged in the black kill switch wire back in and pop goes the fuse.

How can I bypass the kill and still use the starter, have lights, etc?

BomberMann650 · « **Reply #57 on:** July 05, 2016, 03:48:49 PM »

Kills work by grounding out the electrics right? Or do these ones complete a circuit? Can't remember off the top of my head.

Seems to me unplugging the kill bypassed the problem. So your problem lies somewhere between that connection and wherever the other end of that wire goes!

b1jackson · « **Reply #58 on:** July 05, 2016, 04:10:32 PM »

There is also this issue with the button. It still goes in and out it the button is busted.

scottly · « **Reply #59 on:** July 05, 2016, 05:18:38 PM »

Quote from: b1jackson on July 05, 2016, 02:42:55 PM

Unplugged the black wire to kill and the horn and had dash lights, signals. Plugged the horn back in and had beep beep.

Then plugged in the black kill switch wire back in and pop goes the fuse.

Ding ding ding!!! Disconnect the other switch wires, leaving the black wire plugged in, and see if the fuse blows. If it does, the problem is something shorted to the handle bars in the starter housing.

b1jackson · « **Reply #60 on:** July 05, 2016, 05:34:04 PM »

So disconnect the horn wire (black) the brown and just leave the two blacks plugged in?

scottly · « **Reply #61 on:** July 05, 2016, 05:46:41 PM »

No, I meant the other wires in the bundle that comes from the switch housing: The black/red, the black/white, and the yellow/red. If they are all on a single plug, then never mind.

b1jackson · « **Reply #62 on:** July 05, 2016, 05:55:42 PM »

Ah, I see. But maybe an unnessary step unless I wanted to determine if it's in the "kill" side or the "start" side of the switch isn't it? If I am going to put a new switch in anyway, it should be just a plug and play once I figure out how to remove the cables from the throttle grip.

Although frustrating by times (much of the time!) this has been a good exercise in going over the wiring of the bike and fixing up potential future bad connections, adding some shrink wrap where needed, liquid tape, etc. The only light I noticed not working was one signal but that seems pretty easy now!

scottly · « **Reply #63 on:** July 05, 2016, 06:02:59 PM »

Yeah, it would only make sure that the problem is in the switch housing, and not in the headlite, starter, or ignition circuits. It may be something as simple as a wire pinched through the insulation between the two halves of the switch housing.

b1jackson · « **Reply #64 on:** July 05, 2016, 06:11:06 PM »

I had the switch halves pulled apart and couldn't see a pinch anywhere. Given the state that my broken starter button is in, I'd have to say it's there.

But hey, what's one more test?!

Aftermarket switches OK? I see some are available and not too bad of price. Is there a how to or a sticky that covers the swap?

scottly · « **Reply #65 on:** July 05, 2016, 06:28:00 PM »

If it were me, I would try to repair the stock part first, or at least identify the exact fault. Be sure you un-do any changes you made to the solenoid and it's wiring.

b1jackson · « **Reply #66 on:** July 05, 2016, 06:42:05 PM »

Yes, I did see the thread on the switch rebuild and repair but that's way above what I'd want to tackle. The only thing I still have unhooked is the fuse block and I'm still going to replace it with a modern one. I've been careful in reassembly after each test so I don't end up with a mess on my hands.

The PO had a little bolt threaded in the hollow starter button since it was busted so I imagine that the short is in the starting circuit.

scottly · « **Reply #67 on:** July 05, 2016, 07:02:24 PM »

Just for grins, with the switch halves pulled apart and isolated from the handle bar with a piece of heavy paper, see if a fuse blows. BTW, Hondaman makes plug-and-play blade type fuse boxes.

BomberMann650 · « **Reply #68 on:** July 05, 2016, 08:58:51 PM »

4into1.com has replacements.

A former employer of my gave me a rule when I was building his custom bicycles and repairing the shop customers rides.

The rule "If it cost less than $500, replace it."

scottly · « **Reply #69 on:** July 05, 2016, 09:52:44 PM »

Jackson, now that we know what's going on, if you connect the black/white harness wire to a solid black harness wire, it will power up the ignition with the key switch on. To spin the starter, assuming the stock wiring is correct, AND the trans is in nuetral and/or the clutch lever is pulled in, momentarily connect the harness yellow/red wire to 12v. Of course, you could also short the solenoid posts with a screwdriver.

b1jackson · « **Reply #70 on:** July 06, 2016, 01:52:20 AM »

I think I'll just try the "less sparks" method you suggested in post #7 rather that arc the solenoid posts. The secret is now I have ignition!

b1jackson · « **Reply #71 on:** July 06, 2016, 01:54:23 AM »

Quote from: BomberMann650 on July 05, 2016, 08:58:51 PM

4into1.com has replacements.

I see that but the shipping and importing cost is a hassle. Vintage cb750 has them as well I believe.

b1jackson · « **Reply #72 on:** July 06, 2016, 04:11:17 PM »

Quote from: scottly on July 05, 2016, 06:28:00 PM

If it were me, I would try to repair the stock part first, or at least identify the exact fault. Be sure you un-do any changes you made to the solenoid and it's wiring.

I peeled back some tape from the wires going into the kill switch. The black/white one was scorched and rough in quite a few places. The rest were all ok. Just for kicks I stuck in a new black/white at a junction point (the switch must have been replaced once before), hooked everything else up back to stock and popped the fuse again. So that's as far as I am taking it. New switch will be ordered.

The headlight must feed from here too. I've got all lights working but no headlight.

scottly · « **Reply #73 on:** July 06, 2016, 04:47:15 PM »

Quote from: b1jackson link=topic=158975.msg1826533#msg1826533
The headlight must feed from here too. I've got all lights working but no headlight.
[/quote

Yes, the headlight is tied into the starter switch: the black wire is connected to the black/red headlight wire unless the button is pressed, when the black wire is switched to the yellow/red solenoid wire.

b1jackson · « **Reply #74 on:** July 12, 2016, 09:22:43 AM »

New RH switch arrived today so will hopefully be hooking it up tonight. Vintage CB750 had one so will be comparing with wires between the original one and this one and putting it all back together.

Sure.....it doesn't look like the original one but so what. Its hopefully the resolve to all my wiring issues. I have all working ignition now anyway. Horn, signals, dash, etc.

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Author Topic: Need some help trying to start bike with suspected frigged kill switch (Read 20638 times)