Help from the hive mind: Intermittent Starter Issue (2017)

[JRD]

Good afternoon. I have been experiencing an issue with the start button not triggering and wanted to get y'all's takes and see if anyone else has experienced it. I'm handy enough to manage basic maintenance, but electrical is a bit intimidating for me. It's only happened three times so I don't now that I can isolate a pattern or cause. I'll tell you what I know and maybe we can figure it out together?

In all three cases when I turn the key, the electrical turns on, the gauges light up, the dials swing and settle into natural. I then push the button to start and nothing happens: it doesn't click or whir or try to turn over. Simply nothing.

In all three cases I was not starting from cold. Twice I had gotten to my destination, left the bike for 30 minutes or so, and then experienced the fault trying to start it back up. In one case I had turned the bike on, moved it only about 30 feet, turned it off for 1-2 minutes, and then experienced the fault trying to start it again.

Sometimes when I turn the key to the "on" position the bike makes an electrical whir as the electronics kick on (the fuel pump maybe?). That didn't happen any of the times I experienced a fault. Maybe because the bike is already warm? I would have to trouble-shoot more to figure out when exactly that happens and if it matters.

In all three cases I let the bike sit for 5-10 minutes, intermittently kicking the kick-stand up and down, flipping the kill switch on and off, and pushing it in and out of neutral. Eventually it started back up.

On two of the times I remember hearing a slight electronic *click* the last time turning the key back to the "on" position before the successful start.

When it does successfully start it doesn't chug or struggle at all. Starts up clean

Have any of you experienced this on your CBs or other bikes? Or does this sounds like something you know and can diagnose? Any ideas for tests or troubleshooting?

Thanks!

[peterbaron]

My quick guess, without  diags, would be the red kill switch
Rock it several times and see if any improvements. May need to take it apart and check  the inside electric contacts.. or may need further diags??
The side stand switch would by the suspect #2..???

[Lord Popgun]

My thoughts too PB.

Looking at the manual, the circuit is pretty basic but I would check those 2 things first. Both those switches are known trouble spots. They get dirty, corroded or oxidized, etc.

[1973cb750]

check battery connections also a bad battery can do this have it load tested check grounds under the tank and connections on starter relay

[pekingduck]

Sounds like you are diagnosing it well.  I'll add some comments that may help.  Anyone else, please correct me where I'm wrong.

In all three cases when I turn the key, the electrical turns on, the gauges light up, the dials swing and settle into natural. This is normal whether in gear, sidestand up or down, engine switch on or off.

I then push the button to start and nothing happens.  it doesn't click or whir or try to turn over. Simply nothing. This is normal if the sidestand down with trans in gear, or if run switch is off. No whir from the fuel pump means it is not safe to crank.

In all three cases I was not starting from cold. Twice I had gotten to my destination, left the bike for 30 minutes or so, and then experienced the fault trying to start it back up. In one case I had turned the bike on, moved it only about 30 feet, turned it off for 1-2 minutes, and then experienced the fault trying to start it again.

Sometimes (should be always) when I turn the key to the "on" position the bike makes an electrical whir as the electronics kick on (the fuel pump maybe? - Yes). That didn't happen any of the times I experienced a fault. No whir from the fuel pump means it is not going to crank. Maybe because the bike is already warm?  No, it's a cranking circuit interruption. I would have to trouble-shoot more to figure out when exactly that happens and if it matters.

In all three cases I let the bike sit for 5-10 minutes, intermittently kicking the kick-stand up and down, flipping the kill switch on and off, and pushing it in and out of neutral. Eventually it started back up.  It will never crank until you've heard it whir, which is the fuel system being pressurized initially.

On two of the times I remember hearing a slight electronic *click* the last time turning the key back to the "on" position before the successful start. Do you remember hearing the whir? It should have sounded.  Possibly a loose battery connection or faulty battery.  I've had a faulty battery cause similar or same symptoms

When it does successfully start it doesn't chug or struggle at all. Starts up clean That should be expected.

Have any of you experienced this on your CBs or other bikes? Or does this sounds like something you know and can diagnose? Any ideas for tests or troubleshooting? 

[Cormanus]

pekingduck, that all sounds right to me, except that, if I recall correctly, the fuel pump does NOT whir if the ignition is turned on while the kill switch is engaged. Only after you disengage the kill switch with the fuel pump whir. If you're turning on the key, JRD, and not hearing the fuel pump whir, there's likely something amiss with the kill switch.

There are two wires on the front underside of the clutch lever. I've had a starting problem when one or both of those have become disconnected, but I think it's only that the bike has refused to start in gear.

[Lord Popgun]

You are right Cormanus. If the kill switch is engaged the fuel pump does not run.

[Easynow]

I'd like to flag that the fuel pump won't whir (and the bike won't crank) if the CPS (crank position sensor) is disconnected or intermittent.

I think it's the red connector under the right hand cover. It connects to the crank case on the right hand side, in front of your toes. It's also used for diagnostics.

My second suggestion would be to do with the immobiliser in the key, but I don't think US bikes have that.

[pekingduck]

No, the US models don't have the immobilizer.  

And yes, thanks to Cormanus and Lord Popgun and Easynow for clarifying that the pump does not ever run with the kill switch activated.

[JRD]

Y’all, this is great. I will run it down this weekend when I get some time and report back. Thanks so much!