Starter Motor Interlock?

[AdrianS]

Has any one managed to design and fit a locking device to prevent the starter from operating when the engine is running?
I have caught the button on several occasions by accident when the engine is running to be greeted by a terrible screech as the starter gears hit the flywheel. I am sure it is not good for either the starter or the flywheel ring gear!

[boxermania]

Never heard of your experience before as the button is well away from where the hands would normaly reside while riding the bike, however, you are right regarding the meshin noise and the potential ensuing damage.

Maybe you should tape your thumb to your index finger, after starting th bike.....

[NoRRmad]

I went down once at low speed in an intersection in a small town in upstate New York. People standing around converged on me and my bike, maybe twenty feet away. I was a little stunned, and the bike was still running. I heard somebody say, "Hit the kill switch!" Screeeeech! "No, the kill switch!" Screeeeeeeeeeech! "Aw hell, turn off the key!" Engine stopped.

I could see the usefullness of an interlock like that.

[bmwdave52]

Key vs Kill Switch...we should have a debate on what's better.

[AdrianS]

I am no auto electrician but did wonder that if the power supply to the start button ( which I assume only activates the starter relay) was taken from the supply to the red alternator warning light, there would be power to the switch only when the alternator was not charging ie the warning light is on. When the bike starts running the warning light goes off and so would the power to the starter switch. Does that make sense?

[CycleRob]

You can not, must not, tap into the charge light circuit. One side of the bulb has key on power, the other side goes to power the alternator's voltage regulator circuit. When the engine runs the regulator generates a matching back voltage to the key power and the charge light goes out. Drawing enough power to actuate a relay could corrupt it's functioning and possibly overload the regulator's ($$) charge light circuit.

You can use a circuitry like Yamaha once used on an old bike where the AC output from the alternator was used to power a relay coil to turn the headlight on. It was a holding relay circuit, so the light stayed on if the engine stalled or was shut down with the killswitch so the headlight would work with the engine off and the key still on. That same simple diode, rectifier, relay circuit could be created and wired in to prevent the starter from working when the alternator has output. It's not an easy project, as it requires an alternator take-apart and knowledgeable component choices.

A sure fire way to permanently eliminate this starter gear gnashing is to upgrade to an R1200R, F800ST or other newer generation bike with the CAN-Bus BMS-K engine management system. When I press my bike's starter button or hold the button after it starts, the starter will not work with the engine running.

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