I recently worked on a 1984 Honda BIG RED 200ES that had no spark when I bought it. I wrote up this article to give an idea how I troubleshot and resolved this issue. I tried to provide a complete start to finish on this subject so it can be used as a resource to help troubleshoot and resolve a no spark condition on a 1984 200ES BIG RED.
I typically have a particular troubleshooting process I follow testing and evaluating components step by step. This has worked well in the past but in this case it is not always straight forward of pass/fail. That’s ok I like a challenge and increasing my experience so it will be easier to diagnose the next time.
Very basic CDI Ignition theory: In my experience knowing how the system is designed to work is a great help when troubleshooting. It lets you follow the process to know at what point the system is breaking down. The problem here is no spark but getting spark at the spark plug takes a series of events and there is some safety built in (kill switch) which can interrupt the system.
Ok the theory. Again I am going to keep this basic. The BIG REDS use an AC CDI system. This means that a battery is not required to generate a spark.
As the flywheel spins the alternator (mounted under the flywheel and does not spin) creates current.
The current is sent by a wire to the CDI box (Black box mounted on frame under gas tank). The CDI box stores the current until the spark is needed
The pulse generator (mounted in the rocker cover under the cover marked “CDI”) tells the CDI box when the spark is needed. It has a magnet on a rotor. The rotor is driven by the timing chain which is connected to the crankshaft/flywheel. So when the magnet on the rotor passes the stationary portion of the pulse generator it triggers the CDI box to discharges its stored current into the ignition coil.
The ignition coil (mounted on frame under gas tank and has the lead to the spark plug connected to it) amplifies the current and puts it through the spark plug wire and into the spark plug creating a spark.
This cycle repeats itself as the engine rotates.
Background: I bought this 1984 BIG RED 200ES used and not running. The person I bought this from told me that the motor lost spark and has been sitting for a while. I found two CDI boxes in the rear storage area of the ATC so I know somebody probably already attempted to troubleshoot this.
Troubleshooting: Before I start I get a few things ready. I pulled out the service manual, a digital multimeter, and a known good working spark plug. The service manual is important for the troubleshooting guide, wiring diagram, and the specs for testing some of the components. Next I make sure I have access to the components. In this case I removed the gas tank, recoil, timing inspection plug, pulse generator cover, and exposed the wiring in the headlight housing.
Here is the process I followed on this one after I verified that I had no spark at the spark plug: