atv killswitch reversing using a relay?

Im trying to wire up the kill switch on my 89 Honda FL400 Pilot. I installed a Skidoo snowmobile engine in it and i need to change the way the killswitch from the pilot works. Right now, the circut is "open" when the switch is on run alowing the ground to pass through and kill the engine. When the switch is off the circuit is not grounded causing the engine to keep running. I want to reverse the way that works. I know that there is a person that has done this so i know it is possible, he just does not remember how he wired exactly since it has been a while since he did wire it. Can anyone help? ive got a handfull of standard realys laying around so i was wanting to use one of them. I know how to wire up a standard relay to run a high draw radiator fan just a little confused how to do what i want it to here. Thanks in advance!

Instead of the switch being parallel to whatever (probably the grounded ignition points or sensor else ignitor output), route that whatever terminal thru the switch. That assumes typical kill switch circuits that I am familiar with, but things may have changed. It also assumes the switch and wiring handles the re-routed circuit, and some may not, though usually they match the circuit's current capability to ensure voltage drops do not fail to kill.    But note that the kill-switch parallel method is so that a failed switch or bad connection does not kill the engine which is usually more dangerous than a failed circuit that cannot kill the engine. By changing it to series (as I described), any break will kill the engine. (Beware bumps! And aged connectors and switches.) Dare I ask why the change?

I am running an engine from a Skidoo snowmobile in it. The kill circut on the stock pilot was different than the snowmobile. The way i have it set up now is that one side of the on/off switch is grounded and the other side is the ignition kill wire. The way i would like it to work is when this switch is "on" the circut is closed but once you turn it to "off" the circut grounds out the ignition wire. Also, this will NOT be the only killswitch. there is also a key. so if all else fails, the key will kill the engine.

The "standard" kill I described is that in the center position, the switch is open, hence no grounding short across points/timing-sensors/ignitors etc. However most of my bikes had center-on which broke the IgCoil power when killed to either side. I often used that to enable the ignition to be on without having the IgCoil overheat or drain the battery (these were points ignitions before the days of electronic ignitions that only "closed" after a points or sensor (GND) pulse). But I did have a scooter that killed its magneto ignition by GND shorting by the IgnKey in the off position. However upon my first drop (4 days after getting it), the scooter was on top of me with the engine revving flat out (throttle jammed fully open). Turning off the IGN made no difference - the higher magneto output coupled with relatively long and thin shorting wire was not enough to ground the spark. Luckily my gloves minimised the hilarious shock one gets when removing splug plugs from the top of spark plugs whilst sparking. Hence my remarks earlier about adequate wire & switch capacity, however shorting sensors (Hall effect, reluctors, optical etc) should not be an issue, only primary or secondary coil circuits. As to my several "closed for on" series kill switches, I don't recall ever having a problem with unexpected openings, but I could have easily bypassed (ie, bridged out) the kill switch if that was a problem. And despite people advising NOT to use the kill switch to stop my bike engines, I usually did. As long as the switch opens the IgCoil +12V. As so many competition vehicle owners discover, breaking the battery +12V (or -ve) will NOT kill the engine (LOL). [ See my posts about a certain event that STUPIDLY specifies that the (battery) ISOLATION switch must ALSO kill the engine, hence the dangerous practice of a hot (+12V) isolation switch extended into the cabin, and often a rear corner of the vehicle. Battery Isolation switches (to be in the battery GND if mounted away from the battery) are a totally separate function to an engine kill switch. ]

On a technical point, the guts of which I will leave to Oldie, you described the switch as "open". Completely the wrong way round Any open circuit is when NO CURRENT FLOWS.

Oh yeah, I forgot to remember to put that in... I probably got flustered enough referring to a kill switch being OFF for the engine to be ON. Whether that meant open or closed (depending on whether parallel-shorting or series-opening) was yet another dimension. [ And people wonder why we [/]digitals refer to hi & low "logic states" instead of +ve or 0V or even -ve voltages. EG, a typical digital output is HIGH when its output is a LOW voltage (GND) - ie, open-collector or GND switching. ]