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Safety switches

Safety switches

(BTS, December 2004)

Recently I've heard a number of people complaining that it's difficult to find neutral in order to get their bikes started. In fact, our motorcycles should be able to start in gear as long as the clutch is pulled in, but a surprising number of people don't realize this. There are two or three important safety switches on our BMWs which should be working properly, and they are all part of the safety interlock system that protects you and the bike while starting.

The starting interlocks vary by bike model, but typically you only need to be in neutral or have the clutch lever pulled in to start the bike. Some older bikes require that the sidestand is up as well, but newer bikes can start on the sidestand in neutral. If you can only start in neutral, or you have to have the clutch lever pulled in even if you are in neutral, you almost certainly have a bad switch somewhere.

Sidestand switches are a different story because in addition to disabling the starter, they can stop the motor. Depending on the model of bike, this switch either kills power to the control unit (disabling the starter and the ignition) or disables the ignition alone, usually only if the bike is in gear. You might have noticed that if you deploy your sidestand while the bike is running in gear, it kills the engine.  The same thing can happen if the switch starts to make poor contact while riding, making it more problematic than the other two switches mentioned.

It's really important that you know how your bike is designed and then make sure that it works as intended. Stalling your bike in traffic is a minor annoyance if you can pull the clutch in and restart, but potentially lethal if you first have to find neutral with traffic bearing down on you.

Also, you should know how to deal with this on the road if one of the switches fails or becomes unreliable. First, if your bike won't start you should get into the most foolproof condition - neutral, clutch in, and sidestand up - to see if that fixes the problem.  If so, one of those switches is bad.

On early Oilheads the sidestand switch alone will keep the bike from running; follow the wires from the sidestand to the connector under the left side of the seat. If you can bridge those two wires, either in the connector or by cutting and joining the wires between the connector and the switch, you will fool the bike into thinking the sidestand is always up.  With the clutch switch, doing the same thing will make the bike think the clutch lever is always pulled in. The neutral switch works the same way also, but take note that most Oilheads have a gear position switch in addition to the neutral switch, so you need to know which one to mess with, and K-bikes don't have a separate neutral switch at all.

If you have to short out a switch to get your bike working, keep in mind that your bike isn't really working, it's starting and running but lacking an important and you really need to get the switch replaced and restore the proper function of the bike. Even experienced riders who think they don't need these interlocks make mistakes once the interlocks are disabled. It's in our nature to start to rely on systems that always work for us. Likewise, if you are simply working around a bad clutch switch or neutral switch by relying on the other, you should deal with that also lest a second failure leave you stranded on the road somewhere.