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Discussion Starter · #1 ·
Hi all! I'll be hitting the introduction thread here pretty soon, but right now it's a little late. I'm at the very late stages of a CM450C restomod, and I've found that while the starter works and the engine kicks over, it only does so on rare occasion. I'm getting a good connection to ground from the 15v and 7v fuses all the way up to the ignition, but no lights, and no signal to the starter solenoid. For the most part. On my second or so attempt, nothing happened for a good minute and a half after I'd released the button, then the starter kicked the engine over once (giving me quite the scare). In trying to diagnose the issue it's happened several times since, but nothing consistent. The entire time it was on it's center stand and the handlebars were never moved. The yellow/red wire from the start button yields no signal most of the time, nor does the black wire in the red connector inside the headlight bucket, but I do get good signal from several other lines in that connector.
 

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Follow that black wire in the red connector. You may find that you have a poor ignition switch connection or switch. Black wire feeds the right pod (and almost everything else) from the ignition switch. The power from that black wire at the right pod is then diverted, through the starter button contacts to the blue/red (can't remember if tracer is red). That powers the headlight. That same black wire , when the starter button is pressed, diverts power from the blue/red wire to the yellow/red wire. (No power to headlight while starter button is pressed). Power from the yellow/red goes through the solenoid switch to ground, closing the contacts in the solenoid switch and supplying full battery power to the starter motor.
I hope this helps you trace the poor connection situation you are experiencing.
You should download the excellent color wiring diagram that one of our helpful members has taken the time and effort to help us.
 

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Ever time you move the handle bars, the main loom by the headstock also moves. The metal wires inside the loom also move and eventually ( it takes years ) these metal wires work harden, fatique and break, resulting in a make and break contact inside the wire.

Ever wire in the loom suffers, some more than others.

This included the solid red wires from the battery/fuses to the ignition switch, the battery feed to the ign switch, and also to some extent the solid black wire from the ign switch, the switched 12v feed after the ign switch.

The green earth wire is also effected.

There have been instances for the red wire coming off the soldered terminal on the back of the ign switch, as well as make and break contacts inside the loom wires in the area of most flexing.

Do any of the lights etc. misbehave and "flash" / fail to work properly and consistently when the handlebars are turned form lock to lock.

The neutral light/oil light/tail light are a favourite as they are relatively "thin".

Of course you main loom may be absolutely fine, but others should take note of this "problem" for future reference.

Get a wiring diagram/schematic.
 

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Discussion Starter · #5 ·
I haven't had time to look at it for a few days, but to what I remember the connections throughout the wiring loom looked pretty good. I'll still give it a run through just to make sure.

Dtsmjr8dan, your description really helped me out! I have both the fsm and a color wiring diagram, I've just always had a bit of difficulty interpreting wiring diagrams and such.

And as for the lights and whatnot, I'm not really sure. I'm not getting anything to the rear right now but this is the first time since I bought the bike that it has been in a state where they might work.
 

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The wiring diagrams are real easy, just think of them as road maps. A dieing art in these modern times of sat nav and soon to come driverless cars !
 
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