xb12s sometimes doesn't start

[Cooter]

Yes.

Notice how, Key on/red run switch off, the lights are on, gauges sweep like normal. Then turn on the run switch and the fuel pump runs.
The Red run switch controls that ignition relay, so if theres corrosion in the right hand handle bar switch (where the Yellow start switch is) it will affect that relays operation, just like a bad relay does.

So, swap in a new IGN relay and I still think you should remove the right hand handlebar control and clean the yellow start switch contacts, and now clean three run switch contacts as well.. Or buy a new control. They are cheap.

FYI. Everytime you cycle the fuel pump it [can] inject fuel into the cylinders. You can foul the plugs that way with repeated testing.

Put in a relay, clean or replace the right control, and ride it normally. See if the problem returns:up:

Edit in brackets, I was wrong.

 

[Jurrien]

Ok, thanks, I'm going to take a look at the handlebar control also.

And I was not aware that there was fuel injected every time the fuel pump primes. So thanks for that warning. I'll start the bike today, I hope it still does after the many testing actions of yesterday.

 

[Outlaw]

I wasn't aware of the Injectors spraying every key/prime cycle either. I thought it waited for cam or crank signal.

 

[Jurrien]

Normally it starts almost instantly and now it took some more crankshaft rotations before it ran. Maybe 5 or so.
Not disappointing after all that fuel pump priming of yesterday.

 

[34nineteen]

Its like the Shoggin Shank Redemption!

 

[34nineteen]

Dont make me call Mrs Garrett on you two!