Calling all electrical gurus

[dbeardslee]

OK, so I'm over at a friends looking at his 80/81 special (not sure on the year) and he had just replaced the fuse block with a TC spade type. He says when he moved the wires he did them one at a time being careful to get them in the correct locations. Unfortunately I didn't have a schematic handy to double check, but that's next on the list.

Anyway, here's the problem - hit the starter button and nothing happens. However, if you jumper it across from the main wire off the battery to the starter wire it starts cranking, so it appears the starter is fine. Here's a pic of my bike showing where we jumpered in green -



We checked the starter switch, and the emergency shut-off switch, and both appear to be working properly. In checking the parts fiche it appears that this model doesn't have the tip switch, but does have a nuetral safety switch and then there is the relay (might be using the wrong term - the part in the picture) itself - is that correct? Is there anything else that could interupt the connection? I haven't read anything on the relays going bad, but is there a way to test it just to make sure?

Also, just to double check - from the manual it looks like the way it should be wired (by wire color) is red to red on the main fuse, blue to blue, red w/white stripe to brown, brown to brown, and red with white stripe to brown - is that correct? Also, my manual doesn't show the amperage of the fuses on each connection. Anybody know?

[DGXSER]

Hey Doug, According to ole Thunderstruck, you jumpered across your starter solenoid.

My main fuse is on the left side of the bike still. I had four fuse sin the main block and an aux. When I installed the "TC" fuse block, I put the aux in there.

Mine go from left to right looking at the fuse block as follows

Tail - Blue in - Blue out - 10 A
Head - 14 Ga Tan in - Red/Yellow out - 10A
Signal - 12 ga Tan in - 12 ga Tan out - 20 A
Ignit - 14 ga Tan in - Red/White out - 10 A
Aux - Red in - No fuse or out as I am not using this.

That neutral switch just lights the light on mine, it does NOT stop the engine from turning over. In my CLymers I could not find any wiring diagram that labeled the infamous Tip-Over Switch. No idea where that is on my bike or if I have one.

HTH

Don

[dbeardslee]

Don - Thought I was using the wrong term. So how do you test the solenoid?

[Ivan]

I have an 81 special, and it wont crank in gear, unless the clutch is pulled. I would find a test light and check the small leads going to the solenoid. I think yamaha uses the push button switch to ground the primary circuit, so you should have power to BOTH leads with the button not pushed, with the button pushed, you will probably get a dim light on one and nothing on the other, or nothing on either if everything is working. This is all contingent on the button providing the ground.

If you push the button and still have light on both primary leds, then look upstream toward the starter button.

I dont really get the wiring diagrams for these things, I am colorblind, and used to the positive being at the top of the page and the current flow downward. If I get a chance I will look into the diagrams tonight, and see if I can be more clear.

Hopefully someone will chime in and correct me if I am wrong...

[dbeardslee]

Ivan - Are you talking about the red and green wires that come in from the upper left corner of the solenoid? Also when testing, should the test light connect from the main power connection to those wires (individiually)?

[DGXSER]

Ok Doug, I am not an electrical guru, just own the same bike and not color blind. So I could give you that much. I will try to analyze the wiring diagram for you. Some smarter may tell you I am wrong for sure.

From what I see, you jumpered out everything including the solenoid. the other items I see in the sequence to get power to the low side of the solenoid are the ignition switch, if you have power to the tan wires at the fuse panel that would appear to prove the ignition switch is good. Next is the engine stop switch/emergency switch. If you have power to the red white wire at the solenoid (pull the connector apart and check for voltage to ground with a meter I would guess) then that switch should be good to go. Next item would be the Starter Button which should be the blue/ white wire and seems to actually complete the ground path of the low side of the solenoid. So if you know the starter button is completing the circuit and you are sure your emergency switch is good, and you are certain your new fuse is good. I would clean your grounds to the frame good.

If none of that helps, sounds like a bad solenoid to me. But again, others may know better for sure. I know just enough of this sparky stuff to be dangerous!

As a follow up after reading Ivan's post, I just went out and verified. On my 81 special, with the bike in gear, the clutch lever released/engaged clutch, the starter WILL turn the engine over and move the bike! Nuetral switch just lights the light.

[DGXSER]

Doug,

I suppose a simpler method of testing just the solenoid may be to disconnect the connector at the solenoid that has the red white and blue white wires, jumper the red white wire from the solenoid to the positive side of the battery, and then jumper the blue white wire to the negative side of the battery. If the starter does not turn, you probably have a bad solenoid.

[Ivan]

Ok, so the button does complete the ground.

You jumped the high side to get it to crank, this verifies there is sufficient power to run the starter available.

The low side (small wires) should have power to them with the switch on and the button not pressed. Hook a test light tothe negative terminal of the battery, It should light when you probe either side of the solenoid, the small wires. If only one lights with the starter button pressed, you have a break in the primary windings of the solenoid, time to replace it. if both sides light up, take them off the solenoid. Only one should light the test light. Now clip the test light to the positive side of the battery and to the one that didnt light up. press the starter button, that should give you a light, if not, look in that part of the circuit.

Oh... if you hit the button and don't hear the solenoid "click" and the circuits all test good, its probably a bad solenoid.

Sorry, I am doing this all from memory, and on my phone, its making my brain fuzz out.

I need to get a camcorder and make a series of videos about this and find some place to host them....

[bikerphil]

I didn't read the whole thread, but if you ground the blu/wht wire on the solenoid at the solder joint, the bike should crank with the key on, providing that you have 12V at the red/wht. HTH

[DGXSER]

I figured that would work Phil, I was trying to completely isolate just the solenoid. If I had to guess, based upon what has been described, I would think the ignition fuse installed may be bad or a connection is not as solid as it could be since it worked prior to the fuse box work and not after from what I read. JAT

[dbeardslee]

Thanks for the replies guys. This will give me a starting point. Unfortunately my uncle sam is expecting a little note from me on Wednesday, and I haven't started writing it yet , so it may be the weekend before I get to try. I'll let you know what I find.

[dbeardslee]

DGXSER and went back over to try some diagnostics armed with a multimeter and a wiring diagram. Electrical stuff is not my best thing, and I have to give full credit to DGXSER - He tested the wires one by one until he came up with one where we couldn't get continuity. Turned out one of the spade connectors wasn't properly crimped on the end of the wire, and that's why it wouldn't go. DGXSER - you da man!

[DGXSER]

DGXSER - you da man!

Last time I checked....after 18 years of marriage you gotta check to be sure sometimes.

Doug and GK had it pretty well sorted when I got there as far as getting continuity across the switches and when we jumpered power fromt he battery straight to the solenoid low side leads, it cranked, so that left the new connector. We had power to the fuse, and after the fuse, but no power fromt he fuse to the E switch, so either connector or wire was bad. Much easier to replace a connector so we cut the connector off and stripped some wire. Held the wire to the fuse block and she cranked. New connector and done. A small scale MOTM!

[dbeardslee]

Last time I checked....after 18 years of marriage you gotta check to be sure sometimes.

lol You impressed me, brother. Well done.