Bike trying to start with key removed?!

[Bian2512]

Ok see if anyone can help out with this one. Pulled up at a petrol station, removed key, opened fuel cap, and bike tried to start, as in started motor started to crank engine. Took key from filler cap, turned on bike, starter stopped cranking. Filled up as normal. Did this intermittently since. Replaced starter motor relay and kill switch (right-hand switch module), both from bmw. Still does it, any thoughts as to next option?
Thanks
Bian

[sudolea]

Strange. Are there accessories installed (more specifically : not from BMW) ? Looks as if the CAN bus is fooled into thinking the starter switch is pressed. Are you in a (any) gear ? Because if you are, it's even more strange (if not even more improbable).

[Bian2512]

No not in any gear, always after I've pulled up and in neutral. Yes I've got a fuse block thingy, you supply it with a permanent live, neutral and a switched live, then you choose how you want each accessories to be supplied, ie phone charger, bike dash cam, inforad etc.
I've had these accessories fitted for over a year, no trouble.
Are you saying these are the culprits?
Les

[sudolea]

...
Are you saying these are the culprits?
Les

No, rather not (in this case)...

[Sutty]

can you tell if the starter is operating when your moving ?

mick

[Andym535]

A short in the ignition switch perhaps?

[Philip]

Strange indeed.

In your initial post you said " Pulled up at a petrol station, removed key ", removing the key from the ignition switch should immediately remove all power, except that the Sat Nav & accessory plug remains powered for a couple of minutes.

But for the starter to operate, the bike needs to be powered up ( ignition switched on ) AND the started button pressed. Can't see there being 2 wiring faults present at the same time.

To start with ( excuse the pun ), I would remove the power feed wire from your fuse block thingey, just in case there is wiring mistake there.

If that doesn't work, remove the plug from the ZFE ( black box located on the left near the radiator, controls everything electrical on the bike ) & check for any corrosion or moisture in there.

[farmer]

might be worth checking where your permanent power lead comes from for your ancillary switch, starter motor is a good 12v source but if theres something wrong....frayed wires , dodgy switch etc the power would go the other way and turn the starter without starting it. ignition switch could also be a culprit. does it only do this with the stand down and in neutral as this may provide a clue that the safety switches are breaking the circuit
or being by-passed.   

[Tractors are go]

My 13R went through similarish problem. Key removed sidelights stayed on an 2d dash was lit up, first time it did it; was a dry bike run. Next time pissing down in centre of Edinburgh.

Replaced bottom half of ignition barrel, no problems since.

[Bian2512]

Update:-
Think ive sorted it.
After buying a new kill switch/starter switch (£143!!) and still having the same problem, figured its got to be a short somewhere, so started to strip everything back and start tracing through the wiring loom. Found the small + wire that comes from the starter switch to the starter coil twisted around the thick main + that goes to the starter motor and looked like it had vibrated and worn through the insulation. This then meant it could energise the coil, pulling the contacts together for the big thick cables,and try to start it. Also on further investigation after knackering another starter coil, found part of the starter coil had got very very hot, so pressume it had been energising it as i was riding, thus draining the battery. Just waiting for a new genuine bmw starter coil/relay to come so i can verefy what ive just said. As ive bought a new starter switch, but actually checked out ok, i think im going to fit it anyway, just to be sure, and also the original red starter button had gone a fetching shade of pink.
Thanks for the tips guys, c u soon
Bian

[farmer]

always nice to get a victory!!!!
make sure to put whichever switchgear you don't use away safely and marked as good 'cos it will probably come in useful.
well done in the electric war.

[Phmode]

Jeez! Vibration in the cable department on a K. Whoda thought it. Something else to worry about.

Nice result though.