what will make a coil pack it in?

I have a 78 650b that has gone through two coils on the #2 & 3 cyl side in 1 1/2 years. Is there something that would cause a coil to pack it in, or is it just coincidental? :blink: :blink:

Does bike have "points" ignition?

Good Fortune!

Running a coil with too low Ohms rating for the bike will shorten it's life severely due to heat stress.

Leaving the key on will fry them. Roy

What brand of ignition coil are you using? Kawasaki? Dyna? Accel? Emgo? New or used?

I have a dyna s ignition, and the 3ohm green coils. It seems to only be the left coil (cyl 2&3) that goes.

Checked the input voltage to the inition coils? When replacing the bad coil, did you ohm check the bad one? I'm wondering why it failed. How's the mounting configuration? The same for both coils? Did you use a good crimper for the ring terminals on the green coils? If the ring terminal mounting hardware screws are too long, the screws will bottom out before being tight, possibly causing surges in the primary windings.

Read this for the correct crimpers to use:

www.pbase.com/mainecruising/wire_termination
(The Good, Bad, & Ugly Wire Crimpers)

Would also assure the terminal screw head isn't shorting out against the coil mounting spacer.

Good Fortune!

yes I did check and the primary was 4.8 ohms and the secondary did not register at all. Got about 8 months service out of it before it packed it in. The right coil primaries are the same and I forgot what the secondaries where. All the connections were tight not touching anything to short them out. Haven't checked the voltage going to the coil though.

That was an informative link Mfolks. I used a cheap crimper to attach the connector, but they seem tight though.

Could check charging system to assure the battery isn't being over-charged.

Voltage measured across battery terminal posts isn't supposed to exceed 15 volts at 4,000+ rpm.

If charging voltage exceeds 15 volts, may require a new regulator.

Good Fortune!

For quality electrical crimps in a production facility, they only use the ratcheting type crimpers seen toward the last few pages of the article. When I worked at General Dynamics/Convair on the missile programs, the crimpers were calibrated for 30 days, after that time,they were checked with special tools and conducted a pull test to see what level of effort was needed to pull whatever gauge wire was needed out of the terminals.