Ignition coils can fail internally, leaving one cylinder running but no spark in the other side.
Primary(small wires) side of the coils will read between 1.8 to 3.0 ohms.
Secondary(sparkplug wire ports)side of the coil will read between 10.4K to 15.6K ohms. These ports are wired together.
The sparkplug caps should read 5K OHMS(5000), any higher, or a reading of infinity means new caps should be ordered. When re-installing the old or new sparkplug caps, cut about ¼” off the sparkplug wires for a new un-corroded connection.
If the ignition cois are bad(most go bad from age,heat & vibration),read this:
Ignition Coils And Sparkplug Wire Choices
What came with the bike, were ignition coils that even when new were marginal, add years of cooking under the tank in the stop and go traffic, and the coils will probably fail when hot.
Replacement coils can be bought at
www.z1enterprises.com
I believe “Emgo” is the brand. They also carry the popular Dyna 2.2 and 3 ohm coils, along with replacement sparkplug wires.
Now, you have a choice on sparkplug wires:
1.Copper plug wires with no supression caps (the best choice, but will produce audio noise Radio’s and TV’s). Not only do the copper core wires deliver better spark, they will also deliver a much longer lifespan - carbon core wires are prone to erratic spark delivery and early breakdown, short lifespan.
2.Copper plug wires with supression caps(a built in 5000 ohm resistor, that can sometimes fail, like what came with the bike).
3.Copper plug wires with no supression caps, but using resistor plugs(the “R” in the plug number, like B8RES).
4.Supression plug wires with no supression caps.
NEVER use resistor plugs and supression caps or supression plug wires, as now there will be two (2) sources of resistance in the secondary windings of the ignition coils, greatly reducing the spark energy.
Another choice is the Accel 3 ohm coils, with a similar, primary(small wire)electrical connection, using ring terminals as the Dyna ignition coils do. Whatever brand of coil you go with, make sure the primary wires will clear the mounting hardware, as the spacers come awfully close, possibly blowing a fuse. Some riders have replaced the metal spacers with non conductive Nylon spacers, reducing the chance of an electrical problem.
7mm sparkplug wires will fit the stock ignition coils(if they have replaceable wires, indicated by screw off caps on the coils with ridges). The sparkplug wires fit into a port with a brass ”Stinger” that goes into the sparkplug wire or lead(the Brit’s. Canadians, and other countries call the sparkplug wires “High Tension Leads”).
