No neutral light, no spark issue

[Atc70noob]

So I have a 86 big red 250. I can turn the key on and get my starter cranking but I have no spark and no neutral light. I grounded out my neutral safety switch on the frame and I can get the reverse light to turn on but not the neutral light. I know both bulbs are good. Where do I start? When it died it sort of flickered the neutral light and slowly died off and then no spark and no light. My headlight works fine. Anyone ever have this issue?

[SPD FRK]

I have a similar issue. All I have is a possible work around.
Down near where the swingarm attaches to the frame you will find the connection for the neutral light. Disconnect it and try to start it.
You'll have to kick it since the starter motor depends on that connection for a ground.
After my '85 is started I can reconnect the wire.
I will add with mine connected the starter rolls over fine and the light works but no start. Disconnected no starter and no light but it kicks over and runs fine. Also it won't shut off with the key while disconnected sometimes.
I'll be watching this thread to see what you figure out. Could also be my issue. Good luck.

[Flyingw]

On the pigtail for the neutral and reverse lights there is a diode. A diode allows current to flow in one direction only. Sort of like a check valve. If you look at the diagram, the diode is connected to the Light Green/Red wire coming from the neutral switch which provides ground to the neutral light, starter solenoid, and CDI. The diode prevents current from back feeding back through the system. Now, with normal operation, the ground would travel up to the light turning it on, it enables the starter solenoid, and also tells the CDI the transmission is in neutral.

Let's assume the diode is bad, this would prevent the ground from getting to the light. It would also depending If the diode was open or shorted not tell the CDI it is safe to start cutting off the signal to allow the CDI to fire the ignition coil to start. Since the light does not illuminate, I will assume the diode is open just the same as cutting the wire. There is nothing else in the system that would account for the light not illuminating and no fire from the CDI. Disconnect the wires back on the tail and the motor will turn and not fire with estart.

To get to the diode, you have to remove the pigtail the lights plug in to and unwrap the harness for the neutral light. A few inches from the light socket, you will find a tiny black carbon cylinder. Most meters have a diode function. If you put the meter on that setting, you can put the leads on either side of the diode and you will have continuity. Flip the leads and no continuity. This will be the indication for a good diode. If you have continuity in both directions or no indication on the meter in either direction the diode is bad. If you have or can borrow another pigtail then you can verify the pigtail on yours is bad otherwise you can check it with a meter.

You will see attached a wiring diagram with an arrow pointing toward the diode and the symbol for the diode.

[Atc70noob]

My wiring diagram for the 250es does not show that symbol where you indicate it. Could it be that the es model didn't have it? It might be somewhere else in the harness I guess.

[Atc70noob]

Could it be the rectifier? I see the same symbol inside of a box inline with wires coming from the neutral indicator. Looked it up in the earlier pages and it's a rectifier. Continuity in direction of arrow. Could I jump the terminals with a wire and see if the neutral light turns on? That way I can pinpoint what is going on?

[Flyingw]

Yes. That would test the light.

[Flyingw]

The rectifier is actually an inverter rectifier. It's job is to regulate power from the lighting coil at about 13.6vac. It also inverts power from AC to. Dc to charge the battery.

[Atc70noob]

The rectifier is actually an inverter rectifier. It's job is to regulate power from the lighting coil at about 13.6vac. It also inverts power from AC to. Dc to charge the battery.

Do you think it could be my issue? I am at a loss because my skills are basically backtracking all wires and making sure all connections are good. I have not tested any resistances yet and am not sure how. I am pretty sure I can figure it out but I don't have such a good tester, just a cheap harbor freight one.

[Flyingw]

Even a cheap tester will tell you if you have continuity through any given wire and give you a close enough resistance reading. If you touch the leads together, the meter will display the resistance but since the leads are touched together, there will be very little resistance so the display will read 0.00 or a very small number. The smaller the number the less resistance there is and visa versa.

On the 86 ES, Honda moved the diode to a block and since I've never owned one, I can't tell you where that block is but you can find it by the wire colors. This will be a small nylon terminal block with two wires going in to it. The 85 ES diagram does not show the same assembly as the 86 but we know the manuals are full of errors but since yours is an 86 then I fairly confident there is one.

Its very possible in the case of the 85, Honda may have incorporated the diode in to the CDI. In any case, I'm not saying with any certainty that the diode is the problem but its the only component that will effect whether the light turns on and is also connected to the CDI otherwise this kind of problem would be common to both the kick and electric start. If you can find the diode and check it with a meter, that will either confirm or eliminate it as the problem.

To answer your question, anything is possible but the inverter/rectifier is for the charging/lighting systems, not the starter or ignition system.

[Atc70noob]

https://www.dropbox.com/s/mud43xk1nw...819_192529.jpg

If you notice on my schematic to the middle top is the part I am talking about. It runs inline with the neutral indicator light and the neutral switch on the engine itself. There is another bigger regulator/rectifier for the battery as well. We are talking about the smaller one right? The bigger one is for charging, the smaller one is for the neutral light?

[Flyingw]

I'm not sure what you're talking about. There is only one regulator. I put an arrow pointing to the terminal block with the diode. To the left is the fuse block and the right is the CDI.

[Atc70noob]

I re-read your previous post and you are correct, there is a block along the frame near the cdi that has two connectors and a nylon block. It looks like a very small rectangular "relay" like on a car in the distribution box. I disconnected it and observed the spade ends and wondered what it was, I am not sure why I didn't jump the connectors right there but it slipped my mind. I will try to jump the connections ASAP and we will see what happens. I doubt I will get up there anytime soon since the atc is 7 hours from me.

I am quite flustered because I keep finding big reds for sale locally no line but no one ever gets back to me. I may just have to show up and badger these people.

[Atc70noob]

Yeah, what you call the diode I keep calling the regulator. The schematic is calling it a rectifier. Not sure on the proper name but I think it is the culprit.

[Flyingw]

If you disconnect that terminal block and jump across the two wires on the harness side, the light should come on. You don't need to start it, just turn the key on. If the light does come on then we may be heading down the right road. If the light doesn't come on then there is something else going on.

[Flyingw]

This is an ES/SX Regulator/Rectifier. Its mounted on the left side of the tail