will start, won't start, will start....repeat

[BoxerTwin]

I'm chasing an intermittent on my bike.

Sometimes my bike won't start.
I get all the lights, horn works, battery is good, I get a nice neutral light, but press the starter button and nothing. No dip in the voltage, no starter. Just the silence of space.

I have tested kill switch and starter switches. They are in excellent shape.
I have pulled the starter relay and tested it....it worked.

I am getting neutral light so I imagine that I am getting a proper neutral...and the bike rolls without the clutch in so.

Coils are new.

It only seems to do this once the bike it hot. I put about 130 miles on my bike today. Started and stopped multiple times without an issue. Got home, shut off the engine. Went to turn it back on and nothing. I've had this happen a few too many times now. But today I started it and stopped it about 7 times over my 130 miles and 6 hours.

the only thing I can think of is an intermittent in the headlight mess. Could the neutral switch be bad but show a good light?

thoughts?

[ME 109]

Maybe the switch at the clutch lever? It prevents the bike from starting in gear without the clutch lever being pulled in.

Somebody prolly already mentioned it.

[Rob Frankham]

Maybe the switch at the clutch lever? It prevents the bike from starting in gear without the clutch lever being pulled in.

Somebody prolly already mentioned it.

No good I'm afraid... that switch is in parallel with the neutral switch so, even if the clutch switch is shot, the engine will start as long as its in neutral... which it is 'cause the neutral lamp is lit... unless there's another fault as well.

Boxertwin,

First question...

when the bike is acting up, and when you press the start button, do you hear the solenoid... if not, do you hear the starter relay click. If the solenoid goes clunk, the fault is in the starter/solenoid. If not, but you hear the click from the relay, the fault is in the relay or the solenoid or the wires leading up to it. If no click, then it's in the circuit through the starter button to and including the relay. If you can come up with a definitive answer on that, it at least gives you a good place to start looking.

Second question...

what exactly is the bike. There are major differences in the electrics between models and years. It will be much easier to give advice if we know.

Let us know how you get on.

Rob

[BoxerTwin]

Hi,

No solenoid noise.
I'll listen to see if I can hear the relay switch.

The bike a 1977 /7 dressed up like S bike.

The wiring diagrams with their great color coding don't do me much good because to PO resided the bike...poorly. A wiring fault it most likely because I have had to redo a bunch of his 'twisted wire covered in e-tape' hack job. I thought I had it all though so I'm suspecting the mess in the headlight.

[BoxerTwin]

is the neutral and clutch switch normally open or closed....meaning clutch pulled or in neutral, is it open or closed?

thanks,

Glen

[Bob Bennett]

Clutch pulled = closed ie clutch at rest = open circuit

[BoxerTwin]

I hate the wiring diagrams and do better with circuit diagrams.

I made this one that shows all the starter stuff on the R100/7.
It is the bare stuff. It helps me to see what is going on. Maybe it will help you too.

[Rob Frankham]

Hi Boxertwin,

I've taken the liberty of adding a couple of bits to your diagram in the interests of completeness.

Rob

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