Killing the engine.

[Alan]

I'm also none of the above.

My engine is tricky. Sometimes when I turn the choke on... the engine will cut off like it's supposed to. Other times, when it's still cold, it'll keep running, so I have to pull the plug wire since my killswitch doesn't work.

I will be doing the toggle switch before too long, but it's the last thing I'm worried about right now.

Just let out the clutch without any throttle. It will cut. There really is no reason to pull the plug wire.

 

[SirJakesus]

I definitely install a kill switch within easy reach on the handlebar on any build I do for the same reason motorcycles have kill switches. If your throttle gets stuck open you may have trouble choking the engine quickly enough and you wont be able to brake stall the engine in time to save your arse in certain situations. Not having some kind of kill switch is just asking for trouble.

 

[sparky]

Just let out the clutch without any throttle. It will cut. There really is no reason to pull the plug wire.

There is if you've got a centrifugal clutch.

 

[Alan]

You need a kill switch, man.
For now, your hand over the air intake would do it.
Back in the olden days, we used to attach a wire from inside the plug boot to a toggle switch, then back to the frame. It worked.

 

[sparky]

I don't understand how a throttle is just going to stick open.

I know it'd be awesome if I had a kill switch, but it's just that pulling the plug works for now. Turning the choke on should cut the engine off, but it doesn't because there's a leak. I'm going to fix the leaky gaskets long before I get around to the kill switch.

Only reason I can see the need for a kill switch is for a sneaky way to shut off my engine & start pedaling in front of a cop... but luckily, cops don't seem to care about it where I'm from. I've passed tens of cops, and I don't think they even realize I have a motor, honestly.

 

[Alan]

Throttles can stick, and have.(frayed cable, broken return cable, failed spring, debris in cable sleeve, etc.
A lot of bikes have two throttle cables, one is for the return.
Motorcycles have a very large, and bright red kill button.

 

[loquin]

...Unfortunately I have to run twice as many wires for my dynamo system and kill switch, my bike is aluminium and will not conduct.

Aluminum conducts just fine, thank you. Nearly as well as copper. They used to make house wiring from aluminum. (but, it oxidized too easily, leading to electrical fire issues in house wiring if installed incorrectly.) You may have an issue with your motor not being grounded to the frame (mounted on rubber motor mounts, maybe?) or not getting conduction from the handlebar/fork to the bike frame. In either case, you would need to add a second wire.

 

[misteright1_99]

If a wire is run from kill switch directly to spark plug cap, is this as damaging to the magneto as grounding blue wire? Would the kill switch be able to handle the higher output voltage? Food for thought. Old mowers with BS or Tecumseh engines used to have a metal strap attached to head, that you pushed against plug to ground.

 

[graucho]

I definitely install a kill switch within easy reach on the handlebar on any build I do for the same reason motorcycles have kill switches. If your throttle gets stuck open you may have trouble choking the engine quickly enough and you wont be able to brake stall the engine in time to save your arse in certain situations. Not having some kind of kill switch is just asking for trouble.

I totally agree. And its one of the simplest mods we have here. Blue wire from magneto to toggle switch. Then 2nd post of toggle switch back to blue wire from CDI. No magneto frying. No jerking or twisting of motor mounts. Also it shut it down quick passing people with dogs, crabby neighbors, police.

 

[Alan]

Old mowers with BS or Tecumseh engines used to have a metal strap attached to head, that you pushed against plug to ground.

That's exactly what I'm talking about. Same principal.

Does that fry a magneto ? If so, never mind