Shocking while starting...

I recently procured a '79 Batavus and have started to fix stuff on it. I figured I would try to get the engine going first, then deal with less important stuff later. So, I got new spark plug, wire, fuel lines, etc. I managed to get a fat blue spark. However, when trying to start it, I receive a large shock through my arms. I have checked the kill switch and it works fine (and is 'on'), but it is about the only circuit that is good as all other wires are just kind of exploding from the moped. My question: does the whole circuit (bulbs...etc.) need to be in place for me to avoid this shock, or is there a simpler fix?

Any help would be greatly appreciated,


Re: Shocking while starting...

Jason Luther /

to get a nice shock, it has to come from the coil (where the spark plug wire somes out) check to see if it is touching the frame somewhere

Re: Shocking while starting...

I've been shocked from the kill switch wire that goes to the points.. Before repair the kill-switch wires were hanging out bare ended on the handlebars .. and i touched them together to kill the engine.. mild shock. Sometime's i'd feel a shock while riding .. something was arcing or grounding on the bars

Im not sure how many volts the point/condenser wire carries but it's enough to get a mild shock.. nothing like the sharp jolt of the HT coil wire.

Re: Shocking while starting...

The low tension side of the coil should only be 6-12 volts.

The high tenion (sparkplug) side of the coil can be up to 25,000 volts.

Re: Shocking while starting...

something else is going on aside from the 12volts provided by the stator coil... the points definately can arc and a kill wire is connected directly to the points/condenser..

The simple version is points close, coil saturates, points open, plug fires. The amount of time the points remain closed for coil saturation is called the dwell time. The condenser acts as an AC path to ground as the points open, diverting the current flow away from the points, avoiding burning them from drawing an arc as they open. The coils primary inductance and the condenser act as an oscillator when the points are finally open.

blah blah blah.,. but then:

The result is that the primary winding/condenser circuit "rings", increasing the primary circuit voltage above the 12v battery potential, perhaps to several hundred volts.


So, the HT coil voltage is many thousands but, evidently, the primary coil circuit also boosts voltage into the hundreds... i think it's just a characteristic consequence of the points-ignition system design.

Re: Shocking while starting...

Thanks for the info and help.

Here is the update: Of the three outlets from the coil, one is the spark plug wire, one splits and goes (a) through the kill switch and back to ground and (b)blue wire from the magneto, and one goes straight to ground.

Just to check, all things are grounded to the metal bracket surrounding the coil, is this correct?

All of this wiring is good, and i unplugged all other wiring and made sure it is not being grounded. When I touch the handlebars to start it, I dont get shocked. When I pull the choke cable (I havent hooked it to the lever yet) trying to start it is when I get shocked. This doesnt shock me through the thing that attaches it to the handlebars. Is this ok or supposed to happen?

Thanks for reading!

Re: Shocking while starting...

are you asking if you should get shocked when touching the choke cable? hmm... i'd think not :)

might be a clue as to where a bare wire is pinched or rubbing or something.

Re: Shocking while starting...

Everything you have said points to a missing ground wire, probably from the engine to the frame, or from the front fork to the frame.

If you are getting a shock from the choke cable, that means the carburetor (and probably the engine itself) has an electrical potential, with respect to the frame. This should not be - they should be at the same (ground) potential.

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