Topic: Question about kill switch

[smokeygold]

Is it normal for the bike to try to fire with the kill switch in the off position. I noticed this happening over the weekend (starter was whirring with kill switch in off position) but with a dead battery I couldn't check it out. Also, can the bike be kick started with a dead battery.
 The bike is a CB750k4.   Thanks in advance!

[MCRider]

I wouldn't think you'd get any ignition with the kill off. How can the starter turn with a dead battery.

No a CB750 will not start with a dead battery, often not with a weak battery. The alternator is of a design that requires current to enter the coil before it can put current out. It is one of the only models on the road that is this way. You cannot kick start it or bump start it.

[Toxic]

No a CB750 will not start with a dead battery, often not with a weak battery. The alternator is of a design that requires current to enter the coil before it can put current out. It is one of the only models on the road that is this way. You cannot kick start it or bump start it.

I didn't know that... I just assumed you could kick start the bugger to life.

Good to know.

[MCRider]

No a CB750 will not start with a dead battery, often not with a weak battery. The alternator is of a design that requires current to enter the coil before it can put current out. It is one of the only models on the road that is this way. You cannot kick start it or bump start it.

I didn't know that... I just assumed you could kick start the bugger to life.

Good to know.

You would die trying.    The design goes by many names. The one I grew up with is "externally excited field" alternator. As the name says, it need "excitement" from an external source. In this case the battery.

The 500/550 and I think all other SOHC/4s are not this way and you can kick or bump them to life.

[TwoTired]

Alternators need magnets to generate power.  They can be permanent magnets or electromagnets.  All the SOHC4s have electromagnets, meaning you must have electrical power in order to make electrical power.  Without ANY electrical power, the coils won't spark the spark plugs.  You must have a battery to start the SOHC4.

As for kill switches, there are two types; grounding and interrupting.  The SOHC4 uses the interrupting type, as in; it breaks the power flow of electricity to the coils.  If the points are closed, actuating the kill switch, run to stop, can cause the spark plugs for that coil to fire the plugs...once.

Neither of these types of "kill Switches" operate the starter motor.  That is a separate electrical circuit.